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[Coronary artery bypass grafting in patients undergoing chronic hemodialysis: importance of wound healing and hypoproteinemia].

Outcome of coronary artery bypass grafting (CABG) in patients undergoing chronic hemodialysis was studied.</AbstractText>Between January 1996 and August 2004, 49 consecutive hemodialysis patients [38 males and 11 females, mean age 60.0 years (range 47-74 years)] underwent CABG using cardiopulmonary bypass. Duration of hemodialysis was 5.2 years (range 1 month-21 years), and 32 patients were diabetics. Surgery was conducted on the emergency/urgency basis in 12 patients, and intraaortic balloon pumping was placed in 7. Left ventricular ejection fraction was 57.7 +/- 16.3% (range 27-84%). Nine patients underwent concomitant valve surgery. CABG was performed under hypothermic cardiopulmonary bypass and ventricular fibrillation except in one patient, and intraoperative hemodialysis was also performed. Continuous hemodiafiltration was used in the early period after surgery.</AbstractText>Number of bypass grafts was 3.0 +/- 1.0 (range 1-6), and the unilateral internal thoracic artery was used in 29 patients. Operation time, cardiopulmonary bypass time, and aorta clamp time were 313 +/- 87, 145 +/- 63, and 49 +/- 43 min, respectively. Diffuse pericardial adhesion was present in five patients. Severely atheromatous ascending aorta precluded manipulation in seven patients. Although the 30-day mortality was 2.0% (one case), all in-hospital mortality over 9 months was 14.3% (seven cases). The morbid events were mediastinitis in seven cases, reexploration for hemorrhage in seven, pneumonia in two, abdominal complication in three, and stroke in one. Delayed onset mediastinitis was common. Risk factors for death were mediastinitis and serum albumin levels &lt; 3.5 g/dl (both p &lt; 0.05), both of which were wound healing-related factors.</AbstractText>CABG in hemodialysis patients carries a high risk. Patients with hypoalbuminemia appear to require special consideration.</AbstractText>

Prognostic relevance of atrial fibrillation in patients with chronic heart failure on long-term treatment with beta-blockers: results from COMET.

Atrial fibrillation is common in patients with chronic heart failure (CHF). We analysed the risk associated with atrial fibrillation in a large cohort of patients with chronic heart failure all treated with a beta-blocker.</AbstractText>In COMET, 3029 patients with CHF were randomized to carvedilol or metoprolol tartrate and followed for a mean of 58 months. We analysed the prognostic relevance on other outcomes of atrial fibrillation on the baseline electrocardiogram compared with no atrial fibrillation and the impact of new onset atrial fibrillation during follow-up. A multivariate analysis was performed using a Cox regression model where 10 baseline covariates were entered together with study treatment allocation. Six hundred patients (19.8%) had atrial fibrillation at baseline. These patients were older (65 vs. 61 years), included more men (88 vs.78%), had more severe symptoms [higher New York Heart Association (NYHA) class] and a longer duration of heart failure (all P&lt;0.0001). Atrial fibrillation was associated with significantly increased mortality [relative risk (RR) 1.29: 95% CI 1.12-1.48; P&lt;0.0001], higher all-cause death or hospitalization (RR 1.25: CI 1.13-1.38), and cardiovascular death or hospitalization for worsening heart failure (RR 1.34: CI 1.20-1.52), both P&lt;0.0001. By multivariable analysis, atrial fibrillation no longer independently predicted mortality. Beneficial effects on mortality by carvedilol remained significant (RR 0.836: CI 0.74-0.94; P=0.0042). New onset atrial fibrillation during follow-up (n=580) was associated with significant increased risk for subsequent death in a time-dependent analysis (RR 1.90: CI 1.54-2.35; P&lt;0.0001) regardless of treatment allocation and changes in NYHA class.</AbstractText>In CHF, atrial fibrillation significantly increases the risk for death and heart failure hospitalization, but is not an independent risk factor for mortality after adjusting for other predictors of prognosis. Treatment with carvedilol compared with metoprolol offers additional benefits among patients with atrial fibrillation. Onset of new atrial fibrillation in patients on long-term beta-blocker therapy is associated with significant increased subsequent risk of mortality and morbidity.</AbstractText>

Public access defibrillation: suppression of 16.7 Hz interference generated by the power supply of the railway systems.

A specific problem using the public access defibrillators (PADs) arises at the railway stations. Some countries as Germany, Austria, Switzerland, Norway and Sweden are using AC railroad net power-supply system with rated 16.7 Hz frequency modulated from 15.69 Hz to 17.36 Hz. The power supply frequency contaminates the electrocardiogram (ECG). It is difficult to be suppressed or eliminated due to the fact that it considerably overlaps the frequency spectra of the ECG. The interference impedes the automated decision of the PADs whether a patient should be (or should not be) shocked. The aim of this study is the suppression of the 16.7 Hz interference generated by the power supply of the railway systems.</AbstractText>Software solution using adaptive filtering method was proposed for 16.7 Hz interference suppression. The optimal performance of the filter is achieved, embedding a reference channel in the PADs to record the interference. The method was tested with ECGs from AHA database.</AbstractText>The method was tested with patients of normal sinus rhythms, symptoms of tachycardia and ventricular fibrillation. Simulated interference with frequency modulation from 15.69 Hz to 17.36 Hz changing at a rate of 2% per second was added to the ECGs, and then processed by the suggested adaptive filtering. The method totally suppresses the noise with no visible distortions of the original signals.</AbstractText>The proposed adaptive filter for noise suppression generated by the power supply of the railway systems has a simple structure requiring a low level of computational resources, but a good reference signal as well.</AbstractText>

PR and OTc interval prolongation on the electrocardiogram after binge drinking in healthy individuals.

Acute, excessive alcohol intake has been associated with an increased cardiovascular mortality in otherwise healthy individuals. It predisposes to accelerated atherosclerosis resulting in acute coronary events but also arrhythmias have been described, such as atrial fibrillation and life-threatening re-entrant ventricular arrhythmias. QTc prolongation is associated with an increased risk of ventricular tachyarrhythmias and an independent risk factor for sudden cardiac death. The aim of the study is to investigate the effect of binge drinking on the conduction intervals in healthy individuals.</AbstractText>Ten of the volunteers drank red wine while the other ten volunteers drank a sweet designer drink. A follow-up of blood pressure, heart rate, ECG and laboratory findings was performed at an ethanol level of 0, 0.4 and 0.8%, respectively.</AbstractText>Fifteen volunteers showed a prolongation of the PR interval, 13 of the QRS complex, 9 of the QT interval and 13 of the QTc interval. PR interval increased from 149 +/- 16 ms to 163 +/- 11 ms (p &lt; 0.05). The heart rate-adjusted QT interval increased from 400 +/- 24 ms to 426 +/- 52 ms (p &lt; 0.05). Heart rate and systolic blood pressure did not significantly change due to the ingestion.</AbstractText>Acute ingestion of alcohol in a healthy population can induce prolongation of PR and QTc interval.</AbstractText>

[Retrospective assessment of influence of pre-and intra-operative risk factors on early and late surgical results in patients with coronary heart disease and severly impaired left ventricle function who underwent coronary artery bypass grafting].

Aim of the study was to evaluate retrospectively recent and late results of coronary artery bypass grafting (CABG) in patients with ischaemic heart disease and severe left ventricular dysfunction. 146 patients (125 men, 21 women) aged 58.4 +/- 8.4 years, with angina (Canadian Cardiac Society--CCS class &gt; or = 1), heart failure (New York Heart Association--NYHA class &gt; or = 1), left ventricular ejection fraction (LVEF &lt; or = 30%), multi-vessel coronary disease were included to the study. All patients underwent CABG. Peri-operative mortality was 6.1%, in-hospital mortality was 8.2%, 1-year survival was 86.5% and 4-year survival--80%. It was shown that CABG improves angina, dyspnoea and LVEF in patients with coronary heart disease and depressed left ventricle function (LVEF &lt; or = 30%). Selected parameters like: unstable angina requiring intra-aortic balloon pump (IABP) preoperatively, recent heart infarction, cerebrovascular disease, severly depressed left ventricle function (LVEF &lt; or = 20%), mitral regurgitation and Cleveland score &gt; or = 10 pts significantly influence early surgical results (up to 30 days after surgery). It was shown that independent parameters predicting long-term survival and risk of major cardiac events were: negative dobutamine stress test, significant mitral valve incompetence and Cleveland score &gt; or = 10 pts. Use of crystalloid cardioplegia increases early risk of CABG however none of methods of myocardial protection affects long-term surgical results. The outcomes of procedures using blood cardioplegia or intermittent cross clamp and ventricular fibrillation are comparable.

Pneumatosis intestinalis and hepatic portal venous gas after CPR.

Pneumatosis intestinalis and hepatic portal venous gas are usually associated with severe intra-abdominal pathologies. As diagnostic technologies advanced, a number of variant etiologies have been identified. We report 2 cases in which pneumatosis intestinalis and hepatic portal venous gas developed after prolonged cardiopulmonary resuscitation (CPR). The pathogenic mechanism was most probably bowel infarction caused by poor mesenteric perfusion during and after CPR. Limited cardiac output during prolonged resuscitation and severe vasoconstriction after large doses of epinephrine and vasopressors might both contribute to the compromised mesenteric perfusion. The risk seems especially high for old patients with severe atherosclerosis. Once it happens, the prognosis is extremely poor. In patients of cardiac arrests receiving prolonged CPR, catastrophic complications like this should be considered in the postresuscitation phase, especially those with multiple risk factors like old age, severe atherosclerosis, and use of large doses of vasoconstrictors.

The duration of ventricular fibrillation required to produce pulseless electrical activity.

The duration of untreated (no cardiopulmonary resuscitation) ventricular fibrillation (VF) needed to produce postdefibrillation pulseless electrical activity (PEA) was determined in 9 anesthetized swine ranging in weight from 20 to 30 kg. VF was induced electrically by a right ventricular catheter electrode, while arterial pressure and the electrocardiogram were recorded. VF was confirmed by the presence of VF waves in the electrocardiogram and a loss of pulsatile arterial pressure. VF was allowed to persist for 15-second increments (eg, 15, 30, 45, etc), after which defibrillation was achieved with transchest electrodes and the presence or absence of PEA was noted. If PEA was present, rhythmic chest compressions were applied to rescue the animal. Just after initiation of VF and just before defibrillation, VF wave frequency was measured. PEA was encountered in 100% of the trials after 180 seconds of VF. The threshold duration for PEA was 60 seconds. VF wave frequency decreased with the passage of time. At VF initiation, VF wave frequency (f0) ranged from 6 to 15 per second, with a mean of 10.1+/-2.1 per second. At 180 seconds (f180), the mean frequency was 4.0+/-0 per second. It was only possible to eliminate PEA and restore pumping in 1 animal when untreated VF lasted more than 180 seconds. There was no clear transition in the frequency of the VF waves with the passage of time that could predict the possibility of postdefibrillation PEA. Moreover, because of the different initial VF wave frequencies and the different rates of decrease with time, a measurement of VF wave frequency is unlikely to be informative on how long VF had been present. A consistent finding in this swine study of prolonged untreated VF was a rise in blood K+ which increased from a normal prefibrillation value of about 4 mEq/L to 8 to 12 mEq/L at 180 seconds. The longer the duration of VF, the higher the K+.

Antiarrhythmic properties of a prior oral loading of amiodarone in in vivo canine coronary ligation/reperfusion-induced arrhythmia model: comparison with other class III antiarrhythmic drugs.

Amiodarone, which is generally classified as class III antiarrhythmic drug in the Vaughan Williams classification, is widely used for the treatments of refractory arrhythmias. However, we previously reported that intravenous infusion of amiodarone (6.67 mg/kg per hour) did not suppress arrhythmias induced by coronary ligation/reperfusion in dogs. In this study, we examined effects of a prior oral loading of amiodarone on arrhythmias induced by coronary ligation/reperfusion. Sixteen female beagle dogs (8.5 - 12.5 kg) were divided into two groups; one group was given amiodarone (40 mg/kg, orally, n = 8), and the other was given empty gelatin capsules (n = 8) 2 h before the operation. Dogs were anesthetized with pentobarbital and artificially ventilated. The left chest was opened, and the left anterior descending coronary artery was ligated for 30 min and then reperfused. The mean plasma concentration of amiodarone was over 1.3 mug/ml. Although the prior oral loading of amiodarone did not change the QT interval, amiodarone suppressed the number of ectopic beats during coronary ligation and the incidence of ventricular fibrillation during coronary ligation and reperfusion periods (P&lt;0.05 vs control group). In conclusion, a prior oral loading of amiodarone suppressed arrhythmias induced by coronary ligation/reperfusion with a dose that did not prolong the QT interval. This antiarrhythmic property of amiodarone is different from those of the other class III drugs in that antiarrhythmic effects were accompanied by QT prolongation in our all previous studies.

Effect of stress induced by electrical stimulation of the hypothalamus on the electrical stability of the heart in rabbits.

The influence of stress on cardiac electrical stability (CES) and chaotic dynamics of the electrical activity of the heart was studied in acute and chronic experiments in rabbits. Stress was caused by 2-3 h daily immobilization of the animals with electrical stimulation of emotiogenic centers of the hypothalamus through implanted electrodes. CES was estimated by the thresholds for ventricular arrhythmia: paroxysmal ventricular tachycardia, repeated ventricular extrasystoles and ventricular fibrillation (VF). The results showed: (i) CES in stressed rabbits was decreased significantly compared with controls; (ii) the level of chaos at the onset of VF in stressed rabbits was increased significantly compared with controls; (iii) heart rate of stressed rabbits was significantly greater than in controls; (iv) changes in CES parameters depended on whether stress was acute or chronic; (v) acute stress promoted transition of spontaneously reversible VF into spontaneously irreversible VF. Thus, stress increased the degree of disorganization of heart electrical activity and also decreased its electrical stability. The experiments indicate that stress is a destabilizing factor influencing the reversibility of heart rate disorders. The probability of such reversibility depends on whether stress is acute or chronic: acute stress is more likely to lead to irreversible spontaneous VF.

Delayed adaptation of ventricular repolarization after sudden changes in heart rate due to conversion of atrial fibrillation. A potential risk factor for proarrhythmia?

Onset and termination of atrial fibrillation are often associated with abrupt changes in heart rate. Presence and time-course of delayed adaptation of the QT/QTc interval are unknown, but a temporary "mismatch" between rate and the QT interval may enhance the risk of proarrhythmia.</AbstractText>In a prospective two-part study, time-course of adaptation of ventricular repolarization after abrupt changes in heart rate was assessed during termination of Holter ECG-documented atrial fibrillation episodes (Group 1, 32 patients) and subsequently in 20 patients with sick sinus syndrome and cardiac pacing initiating abrupt bi-directional changes in paced heart rate (Group 2).</AbstractText>Conversion of atrial fibrillation showed a 32+/-21 bpm fall in heart rate (P&lt;0.05). Restoration of the QTc interval afterwards was delayed by &lt; or =1 min in 27%, by 1-2 min in 21%, by 2-5 min in 11% and by &gt;5 min in 41% of the cases. Atrial pacing simulating a 30 bpm fall/increase in atrial rate demonstrated that a subsequent transient rate-QT mismatch is a physiological phenomenon (fall of 100 to 70 bpm: initially 90% of the proper QTc interval, compared with 94% after conversion of atrial fibrillation). The restoration curve of QTc adaptation showed an initially fast and subsequently slower time component, with interindividual variation. Clinical parameters, baseline heart rate or the direction of rate changes were not predictive.</AbstractText>Delayed adaptation of ventricular repolarization following atrial fibrillation onset and termination is common, requiring minutes for restoring the QT/QTc steady state. Clinical parameters fail to predict patients with a long-lasting rate-QT mismatch. It may carry a significant arrhythmogenic risk particularly in patients on QT altering medication.</AbstractText>

Cardiopulmonary resuscitation with vasopressin in a dog.

That endogenous vasopressin levels in successfully resuscitated human patients were significantly higher than in patients who died pointed to the possible benefit of administering vasopressin during cardiopulmonary resuscitation (CPR). Several CPR studies in pigs showed that vasopressin improved blood flow to vital organs, cerebral oxygen delivery, resuscitability and neurological outcome when compared with epinephrine. In a small clinical study, vasopressin significantly improved short-term survival when compared with epinephrine indicating its potential as an alternative pressor to epinephrine during CPR in human beings. As there was little clinical data available at that time, its recommended use was limited to adult human beings with shock-refractory ventricular fibrillation. In this report, we present the case of a dog in which the successful management of intraoperative asystolic cardiac arrest involved vasopressin. Unexpected cardiac arrest occurred during anaesthesia for the surgical removal of multiple mammary adenocarcinomata in a 11-year-old Yorkshire terrier. Despite an ASA physical status assignation of III, the dog was successfully resuscitated with external chest compressions, intermittent positive pressure ventilation and vasopressin (2 doses of 0.8 IU kg(-1)) and was discharged 3 days later without signs of neurological injury. We believe vasopressin contributed to restoring spontaneous circulation. It may prove increasingly useful in perioperative resuscitation in dogs.

[Inflammatory, lipid, and metabolic profile in acute ischemic syndrome: correlation with hospital and posthospital events].

To associate the markers lipid profile, inflammatory profile (high-sensitivity C-reactive protein HSCRP and fibrinogen), and metabolic profile (glucose determination) with hospital and posthospital events in patients with acute ischemic syndrome (AIS) and to describe the predictors of mortality in this population.</AbstractText>A cohort study with 199 patients with AIS (unstable angina, acute myocardial infarction (AMI) with or without ST segment elevation) admitted to the intensive care unit (ICU) of a university cardiology Hospital, from March to November 2002. The previous diseases, the medication in use, and the coronary risk factors were recorded. The clinical events considered in the hospital were reinfarction, angina, heart failure (HF), ventricular fibrillation, and death; the posthospital events considered (30 days after hospital discharge) were reinfarction, angina, HF, death, and admittance for percutaneous procedures (PTCA) or for revascularization (MRS).</AbstractText>HSCRP and altered glycemia were significantly associated with hospital events (P = 0.03 and P &lt; 0.01, respectively); however, they were not associated with posthospital events (P = 0.19 and P = 0.61, respectively). Lipid profile and fibrinogen did not have a statistically significant association in any of the times assessed. Using multiple logistic regression, age (P = 0.04), previous AMI (P = 0.04), myocardial infarction with ST segment elevation (P = 0.008) or without ST segment elevation (P = 0.048), and altered glycemia (P = 0.002) were predictors of hospital mortality.</AbstractText>Increased HSCRP and altered glycemia were associated with a greater number of hospital events, whereas age, previous AMI, AMI with or without ST segment elevation, and altered glycemia were predictors of hospital mortality.</AbstractText>

Value of left ventricular filling parameters to predict mortality and functional class in patients with heart disease from the community.

Surprisingly few studies described the value of Doppler parameters in patients from the community.</AbstractText>The aim was to determine the prevalence of prolonged IVRT (&gt;0.105s) or a prolonged EDT (&gt;0.280s) with a reduced E/A (&lt;0.5) in heart patients from the community without valvular, systolic or rhythmic dysfunction. The associations of these parameters to all cause mortality and NYHA functional class were examined as well.</AbstractText>Seventy-two volunteer stable patients with a history of heart disease were identified from general practice. Patients with LVEF below 0.45, valvular abnormalities, atrial fibrillation, and pacemaker were excluded. Routine blood tests, echocardiography, chest X-ray, physical examination and mortality were evaluated.</AbstractText>male 33%, mean age of 68 years, hypertension 82%, ischaemic heart disease 43%, and NYHA class I+II+III in 50+39+11%. Abnormal EDT occurred in 4% (95% CI from 0 to 9%), IVRT in 18% (9-27%), E/A in 0%. None had a restrictive pattern. EDT was longer in NYHA III than in NYHA I-II patients (median 0.25 vs. 0.19s, p=0.0006). E/A and IVRT were not associated with NYHA class or mortality. After 7.4 years 16 of 72 patients died. EDT predicted mortality in univariate analysis but not in a multivariate analysis where NYHA class and gender were the only significant predictors.</AbstractText>Prolonged EDT was weakly associated to NYHA class and mortality while IVRT and E/A were not. Prolonged IVRT was a frequent finding, but a diagnosis of diastolic dysfunction is not supported by mild to moderate abnormal IVRT or E/A.</AbstractText>

Initial, continuous and intermittent bolus cardioplegia administration: efficacy of potassium-chloride and magnesium-sulfate as minimal additives for minimally-diluted blood cardioplegia.

The most effective delivery of blood cardioplegia (BCP) remains controversial, and a combination of initial continuous and intermittent bolus BCP seems to compensate each demerit. However, a large amount of crystalloid solution is infused into the myocardium in this method, which may nullify the advantages of BCP. We examined the hypothesis that minimally-diluted BCP resolves this issue and provides superior myocardial protective effects.</AbstractText>Seventy patients undergoing elective coronary revascularization between 1997-2001 (M:F=55:15, mean age 67.6+/-7.5 years) were randomly allocated into one of 2 groups: Group C (n=35) was given the standard 4:1-diluted blood-crystalloid BCP, and Group M (n=35) was given minimally-diluted BCP supplemented with potassium-chloride and magnesium-sulfate. The BCP temperature was maintained at 30 degrees C. Cardioplegic arrest was induced with 2 minutes of initial antegrade BCP infusion, followed by continuous retrograde BCP infusion. Intermittent antegrade BCP was infused every 30 minutes for 2 minutes.</AbstractText>The time required for achieving cardioplegic arrest was significantly shorter in Group M (47.5+/-16.3 vs 62.5+/-17.6 s, p&lt;0.0001) and the number of patients showing spontaneous heart-beat recovery after aortic unclamping was significantly larger in Group M (28 vs 15, p=0.0029). The number of patients suffering from atrial fibrillation during the postoperative period was significantly smaller in Group M (3 vs 11, p=0.034). The total amount of crystalloid solution infused as cardioplegia was significantly smaller in Group M (62.8+/-22.3 vs 733.6+/-382.6 mL, p&lt;0.0001). Postoperative maximum dopamine dose (3.57+/-2.46 vs 5.44+/-2.23 mg/kg/min, p=0.0014) and peak creatine kinase-MB (19.5+/-8.5 vs 25.8+/-11.9 IU/L, p=0.0128) were significantly lower in Group M. The number of patients showing paradoxical movement of the ventricular septum by early postoperative echocardiography was significantly smaller in Group M (9 vs 24, p&lt;0.0007).</AbstractText>These results demonstrate that initial continuous and intermittent bolus administration of minimally-diluted BCP supplemented with potassium and magnesium can be a simple, reliable and effective technique of intraoperative myocardial protection.</AbstractText>

Anterolateral right thoracotomy for mitral valve procedure after previous coronary artery bypass grafting with functioning internal mammary artery grafts.

Mitral valve procedure after previous coronary artery bypass grafting (CABG) with functioning internal mammary artery (IMA) grafts has high risk. Especially, internal mammary artery grafts injury may be fatal. The anterolateral right thoracotomy affords easy access to the right atrium with minimal dissection, and minimizes the risk of injury to the IMA grafts. We reviewed our operative technique and outcome after mitral valve procedure after previous CABG with functioning IMA grafts.</AbstractText>Thirteen patients (11 male and 2 female, mean age of 67.7+/-8.5 years, range 54 to 80 years) underwent mitral valve replacement after previous CABG with functioning IMA grafts from march 1993 to september 2002. The mean interval between the previous CABG and the mitral valve procedure was 3.8 years (range 9 months to 8 years). Four patients had simultaneous mitral valve procedures at initial CABG (2 repairs and 2 replacements). The operation has performed through the anterolateral right thoracotomy, under ventricular fibrillation with moderate hypothermia and without cardioplesia.</AbstractText>Mitral valve repair was performed in 3 patients, mitral valve replacement in 10 patients. The mean coronary bypass time was 69.1+/-16.2 min (range 45 to 98 min). The operation time was 159.3+/-29.4 min (range 120 to 219 min). Intensive care unit stay days was 1.9+/-1.6 days (range 1 to 5 days). Peak CK/CK-MB values were 555.1+/-290.4 IU/16.6+/-10.7 IU (range 176 to 924 IU/7 to 44 IU). Peak troponin I value was 9.5+/-5.2 pg/mL (range 4 to 17.8 pg/mL). There was no IMA injury and no early death. Other complications were newly arrhythmia in 3 patients, renal insufficiency in 1 patient, reoperation for bleeding in 1 patient.</AbstractText>Anterolateral right thoracotomy approach, ventricular fibrillation with moderate hypothermia without cardioplesia were a safe and good method for mitral valve operation after previous CABG with functioning IMA graft.</AbstractText>

Relation of elevated C-reactive protein and interleukin-6 levels to left atrial size and duration of episodes in patients with atrial fibrillation.

Previous studies have demonstrated inflammation to be a risk factor in patients with atrial fibrillation (AF). In this prospective study of 90 patients with persistent and permanent AF and 46 controls, we found increased C-reactive protein (CRP) and interleukin-6 levels in patients with AF compared with controls (p &lt;0.001). Multivariate analysis revealed CRP to be an independent predictor of AF (p = 0.01). Left atrial diameter was positively related to CRP and interleukin-6 (p &lt;0.001, R = 0.37; p &lt;0.001, R = 0.46, respectively) and negatively related to left ventricular function. Interleukin-6 levels were positively related to AF duration before cardioversion (p = 0.02). Elevation of CRP and interleukin-6 suggest a role of inflammation in AF, and the relation of CRP and interleukin-6 to left atrial size and AF duration before cardioversion indicates that inflammation may participate in the process of atrial remodeling.

Comparison between dobutamine and levosimendan for management of postresuscitation myocardial dysfunction.

To investigate the effects of levosimendan, a nonadrenergic inotropic calcium sensitizer, in comparison with adrenergic dobutamine for the management of postresuscitation myocardial dysfunction following resuscitation from prolonged cardiac arrest.</AbstractText>Randomized prospective animal study.</AbstractText>Animal research laboratory.</AbstractText>Male Yorkshire-cross domestic pigs</AbstractText>Ventricular fibrillation was induced in male domestic pigs weighing between 35 and 40 kg. Cardiopulmonary resuscitation, including precordial compression and mechanical ventilation, was started after 7 mins of untreated cardiac arrest. Electrical defibrillation was attempted after 5 mins of cardiopulmonary resuscitation. Each animal was successfully resuscitated without pharmacologic intervention. Resuscitated animals were randomized to treatment with levosimendan, dobutamine, or saline placebo. The inotropic agents or an equivalent volume of placebo diluents was administered 10 mins after restoration of spontaneous circulation. Levosimendan was administered in a loading dose of 20 microg.kg over 10 mins followed by a 220-min infusion of 0.4 microg.kg.min. Dobutamine was infused into the right atrium in an amount of 5 microg.kg.min. Treatment was continued for a total of 230 mins.</AbstractText>Levosimendan and dobutamine produced comparable increases in cardiac output. However, levosimendan produced significantly greater left ventricular ejection fraction and fractional area changes compared with dobutamine and saline placebo.</AbstractText>Levosimendan has the potential of improving postresuscitation myocardial function. It is likely to serve as an alternative to dobutamine as an inotropic agent for management of postresuscitation myocardial dysfunction.</AbstractText>

Management following resuscitation from cardiac arrest: recommendations from the 2003 Rocky Mountain Critical Care Conference.

To propose a strategy for the management of patients admitted to critical care units after resuscitation from cardiac arrest.</AbstractText>Prior to the conference relevant studies were identified via literature searches and brief reviews circulated on the following topics: glucose and blood pressure management; therapeutic hypothermia; prearrest outcome prediction; post-arrest outcome prediction; and management of myocardial ischemia. Two days were devoted to assessing evidence and developing a management strategy at the conference. Consensus opinion of conference participants [intensive care unit (ICU) physicians] was used when high grade evidence was unavailable. Additional literature searches and data grading were performed post-conference.</AbstractText>High grade evidence was lacking in most areas. Specific goals of treatment were proposed for: general care; neurologic care; respiratory care; cardiac care; and gastrointestinal care. There was adequate evidence to recommend therapeutic hypothermia for comatose patients who had witnessed ventricular fibrillation or ventricular tachycardia arrests. Conference participants supported extending therapeutic hypothermia to other presenting rhythms in selected circumstances. Additional goals included mean arterial pressure 80 to 100 mmHg, glucose 5 to 8 mmol.L(-1) using insulin infusions, and PaO(2) &gt; 100 mmHg for the first 24 hr. Absent withdrawal to pain 72 hr after resuscitation should prompt consideration of palliative care. The level of evidence for other recommendations was low.</AbstractText>The proposed management strategy represents an approach to manage patients in the ICU following resuscitation from cardiac arrest. Most of the recommendations are based on low grade evidence. Additional research is needed to improve the evidence base. A standard post-arrest management strategy could help facilitate future research.</AbstractText>

In-hospital complications of acute myocardial infarction in hypertensive subjects.

Recent studies have shown a worse in-hospital outcome in hypertensive than in normotensive patients with acute myocardial infarction (AMI), which has been attributed to more frequent complications. The aim of this study was to investigate clinical patterns, risk factors, and in-hospital complications in hypertensive and normotensive patients with AMI.</AbstractText>Of 4994 consecutive patients with AMI admitted to the intensive care unit, hypertensive patients with first infarction (n = 915; mean age 68.8 +/- 11.4 years) and 915 gender- and age-matched normotensive subjects were retrospectively studied.</AbstractText>In the univariate analysis, hypertensive subjects presented more frequently non-Q-wave infarction and ST segment depression than did normotensive subjects, even if hypertensive subjects more frequently had diabetes, dyslipidemia, renal failure, peripheral artery disease, cerebrovascular disease, and chronic obstructive pulmonary disease (P &lt; .01 for all). Hypertensive subjects less frequently presented with cardiogenic shock (4.0% v 11.6%; P &lt; .01), atrioventricular block (4.9% v 7.4%; P = .02), ventricular fibrillation (2.2% v 3.7%; P = .04), cardiac rupture (0.1% v 0.9%; P = .02), and ventricular thrombosis (0.5% v 1.5%; P &lt; .03), and a higher frequency of paroxysmal atrial fibrillation (9.2 v 5.6%; P &lt; .01). Mortality was significantly higher in patients with anterior versus inferior infarction, for all normotensive and hypertensive subjects (13.7% v 7.1%; P &lt; .001), but mortality was remarkably higher in normotensive than in hypertensive subjects (17.8% v 6.2%; P &lt; .001), regardless of infarction site (anterior, 11.2% v 4.1%; P &lt; .001; inferior, 4.4% v 1.9%; P &lt; .001).</AbstractText>Hypertensive subjects with first AMI have a better in-hospital outcome than age- and gender-matched normotensive subjects, perhaps due to a less severe extension of the infarction area or to a different pathophysiologic mechanism.</AbstractText>

QT dispersion and early arrhythmic risk in acute myocardial infarction.

This study sought to find out QT dispersion in healthy individuals and patients of acute myocardial infarction and to find correlation, if any, between QT dispersion and the incidence of ventricular arrhythmias in acute myocardial infarction.</AbstractText>QT dispersion was calculated from a 12-lead electrocardiogram in 100 patients of acute myocardial infarction admitted in intensive coronary care unit and 100 age- and sex-matched healthy individuals. In patients of acute myocardial infarction, QT dispersion was calculated on admission, 24 hours after admission and at the time of discharge from intensive coronary care unit. Average QT dispersion in acute myocardial infarction was found to be significantly higher on admission (76.4 +/- 18.3 ms), 24 hours after admission (62.88 +/- 17.52 ms) and at the time of discharge from intensive coronary care unit (51.79 +/- 16.79 ms) than in healthy individuals (29.76 +/- 6.06 ms; p&lt;0.05). QT dispersion was found to be significantly increased in patients of acute myocardial infarction with ventricular arrhythmias (82.06 +/- 16.86 ms) than in those without (66.75 +/- 16.28 ms; p&lt;0.01). Patients of acute myocardial infarction with ventricular tachycardia or ventricular fibrillation had significantly increased QT dispersion (96.25 +/- 15.97 ms) than those who had only ventricular premature beats (80 +/- 15.04 ms; p&lt;0.01). QT dispersion was found to be significantly greater in patients with anterior wall acute myocardial infarction (79.80 +/- 18.19 ms) than in those with inferior wall acute myocardial infarction (71.9 +/- 17.48 ms; p&lt;0.05). At the time of discharge from intensive coronary care unit no statistically significant difference was found in QT dispersion in those who received thrombolysis (51.58 +/- 16.05 ms) and those who did not (48.18 +/- 14.68 ms; p&gt;0.05). QT dispersion was found to be significantly higher in those who died (88.66 +/- 15.97 ms) than in those who survived (74.23 +/- 17.91 ms; p&lt;0.05). QT dispersion was significantly higher in ventricular arrhythmic deaths (97.14 +/- 17.04 ms) than those who had non-arrhythmiac deaths (81.25 +/- 11.25 ms; p&lt;0.05).</AbstractText>Interlead QT variation and its measure as QT dispersion challenges our current approach to the electrocardiographic assessment of arrhythmic risk. QT dispersion may provide a potentially simple, cheap, non-invasive method of measuring underlying dispersion of ventricular excitability.</AbstractText>

Sudden cardiac death in a child affected by Prader-Willi syndrome.

A case of sudden cardiac death in a 3-year-old young male affected by Prader-Willi syndrome, clinically diagnosed and confirmed by means of DNA methylation, is presented. The infant suddenly collapsed at home and was taken apparently unconsciousness by his mother to the emergency clinic where he was pronounced dead. A complete postmortem examination was performed and the histological findings led to the definition of cardiac death with a typical picture of contraction band necrosis. Pulmonary hypoxic alterations are frequently reported as the primary cause of death in PWS cases. In this fatal case according to the macroscopic and microscopic findings, the cause of death was most likely cardiac and possibly related to contraction band necrosis linked with ventricular fibrillation and sudden death.

Implantable cardioverter defibrillator storm: nursing care issues for patients and families.

Implantable cardioverter defibrillators (ICDs) are being used for primary and secondary prevention of life-threatening cardiac arrhythmias, and evidence suggests that increased use is likely in the future. ICD storm, the delivery of two or more shocks within 24 hours, occurs in 10% to 20% of patients who have ICDs and can have long-lasting psychological and physical consequences. An understanding of the factors associated with ICD storm, relevant assessment, and patient and family teaching and counseling can help clinicians to better meet the needs of patients who have experienced ICD storm.

Atrial fibrillation: profit from cardiac pacing?

The impact of cardiac pacing on the prevention of atrial fibrillation is under scientific investigation. Several prospective randomised clinical trials have reported that atrial-based "physiologic" AAI(R)- or DDD(R)-pacing is associated with a lower incidence of paroxysmal and permanent atrial fibrillation than single-chamber ventricular pacing in patients with a conventional pacemaker indication. However, it is still uncertain whether atrial pacing itself has independent antiarrhythmic properties. In contrast, right ventricular pacing is considered to promote atrial fibrillation, even in preserved AV synchrony during dual-chamber pacing. The electrical secondary prevention of atrial fibrillation is mainly based on variations of the atrial pacing site and sophisticated preventive pacing algorithms incorporated in the pacemaker software. Dual-site right atrial and biatrial pacing were reported to exhibit modest to no benefit for the prevention of atrial fibrillation, whereas septal pacing and specific preventive pacing algorithms have been demonstrated to reduce the incidence of atrial fibrillation in a number of clinical trials. However, the role of septal pacing and preventive pacing algorithms still has to be clarified since, overall, study results have been inconsistent so far. One of the main goals of future investigations should be the identification of responder groups of preventive pacing concepts. In clinical practice, the efficacy of pacing algorithms and septal pacing has to be determined in the individual case. These options should be taken into account in patients with symptomatic bradycardia as the indication for cardiac pacing and, in addition, symptomatic atrial fibrillation.

Common variants in myocardial ion channel genes modify the QT interval in the general population: results from the KORA study.

Altered myocardial repolarization is one of the important substrates of ventricular tachycardia and fibrillation. The influence of rare gene variants on repolarization is evident in familial long QT syndrome. To investigate the influence of common gene variants on the QT interval we performed a linkage disequilibrium based SNP association study of four candidate genes. Using a two-step design we analyzed 174 SNPs from the KCNQ1, KCNH2, KCNE1, and KCNE2 genes in 689 individuals from the population-based KORA study and 14 SNPs with results suggestive of association in a confirmatory sample of 3277 individuals from the same survey. We detected association to a gene variant in intron 1 of the KCNQ1 gene (rs757092, +1.7 ms/allele, P=0.0002) and observed weaker association to a variant upstream of the KCNE1 gene (rs727957, +1.2 ms/allele, P=0.0051). In addition we detected association to two SNPs in the KCNH2 gene, the previously described K897T variant (rs1805123, -1.9 ms/allele, P=0.0006) and a gene variant that tags a different haplotype in the same block (rs3815459, +1.7 ms/allele, P=0.0004). The analysis of additive effects by an allelic score explained a 10.5 ms difference in corrected QT interval length between extreme score groups and 0.951 of trait variance (P&lt;0.00005). These results confirm previous heritability studies indicating that repolarization is a complex trait with a significant heritable component and demonstrate that high-resolution SNP-mapping in large population samples can detect and fine map quantitative trait loci even if locus specific heritabilities are small.

Quantitative determinants of the outcome of asymptomatic mitral regurgitation.

The clinical outcome of asymptomatic mitral regurgitation is poorly defined, and the treatment is uncertain. We studied the effect on the outcome of quantifying mitral regurgitation according to recent guidelines.</AbstractText>We prospectively enrolled 456 patients (mean [+/-SD] age, 63+/-14 years; 63 percent men; ejection fraction, 70+/-8 percent) with asymptomatic organic mitral regurgitation, quantified according to current recommendations (regurgitant volume, 66+/-40 ml per beat; effective regurgitant orifice, 40+/-27 mm2).</AbstractText>The estimated five-year rates (+/-SE) of death from any cause, death from cardiac causes, and cardiac events (death from cardiac causes, heart failure, or new atrial fibrillation) with medical management were 22+/-3 percent, 14+/-3 percent, and 33+/-3 percent, respectively. Independent determinants of survival were increasing age, the presence of diabetes, and increasing effective regurgitant orifice (adjusted risk ratio per 10-mm2 increment, 1.18; 95 percent confidence interval, 1.06 to 1.30; P&lt;0.01), the predictive power of which superseded all other qualitative and quantitative measures of regurgitation. Patients with an effective regurgitant orifice of at least 40 mm2 had a five-year survival rate that was lower than expected on the basis of U.S. Census data (58+/-9 percent vs. 78 percent, P=0.03). As compared with patients with a regurgitant orifice of less than 20 mm2, those with an orifice of at least 40 mm2 had an increased risk of death from any cause (adjusted risk ratio, 2.90; 95 percent confidence interval, 1.33 to 6.32; P&lt;0.01), death from cardiac causes (adjusted risk ratio, 5.21; 95 percent confidence interval, 1.98 to 14.40; P&lt;0.01), and cardiac events (adjusted risk ratio, 5.66; 95 percent confidence interval, 3.07 to 10.56; P&lt;0.01). Cardiac surgery was ultimately performed in 232 patients and was independently associated with improved survival (adjusted risk ratio, 0.28; 95 percent confidence interval, 0.14 to 0.55; P&lt;0.01).</AbstractText>Quantitative grading of mitral regurgitation is a powerful predictor of the clinical outcome of asymptomatic mitral regurgitation. Patients with an effective regurgitant orifice of at least 40 mm2 should promptly be considered for cardiac surgery.</AbstractText>Copyright 2005 Massachusetts Medical Society.</CopyrightInformation>

Commotio cordis--a report of three cases.

Commotio cordis is a recognised cause of sudden death in which an apparently minor blow to the chest causes ventricular fibrillation and cardiac arrest. It is best known for causing death during games of youth baseball in the United States, but individual cases have been recorded as a result of a wide range of activities, principally sporting. The underlying biochemical and mechano-electric causes have been well documented. However, there are few reported cases where commotio cordis is implicated as the cause of death in homicide cases. We present three cases from the north-east of England where an assault caused death by this mechanism.

Implantable dual-chamber defibrillator for the selective treatment of spontaneous atrial and ventricular arrhythmias: arrhythmia incidence and device performance.

Atrial tachyarrhythmias are a common co-morbidity in patients with an ICD indication. Recently introduced ICD's are equipped to independently detect and treat atrial and ventricular tachyarrhythmias. The purpose of this prospective study was to evaluate the incidence and termination of spontaneous atrial and ventricular tachyarrythmias in patients with a history of atrial tachyarrhythmias.</AbstractText>Ninety patients, 70% male with an ICD indication and history of atrial tachyarrhythmia (LVEF 45 +/- 6%, [AT/AF indication 55 +/- 10, AT/VT 45 +/- 16], 46% CAD) were enrolled and 89 were implanted with a VENTAK PRIZM AVT (Guidant). Spontaneous atrial and ventricular tachyarrhythmias were printed and evaluated during an average follow-up period of 272 +/- 72 days utilizing the stored intracardial electrogram function of the device. Nineteen patients (21%) presented had only atrial tachyarrhythmias, 32 patients (36%) had both atrial and ventricular tachyarrhythmias and 18 patients (20%) had only ventricular tachyarrhythmias. Patients with only atrial tachyarrhythmias had a total of 3274 atrial episodes; 2002 terminated spontaneously, 1264 were treated with ATP and 8 with shock therapy. ATP was successful in 735 (58%) of 1264 episodes. Patients with both atrial and ventricular tachyarrhythmias had 7277 documented atrial tachyarrhythmias, 5231 terminated spontaneously, 1153 of 2009 were terminated by ATP (57.4%) and 37 by shock therapy (20 patient controlled). Atrial tachyarrhythmias identified as atrial flutter (AT) by the atrial rhythm classification (ARC) algorithm had a higher ATP conversion success rate than episodes identified as atrial fibrillation (AF); 66.7% for AT and 26.4% for AF. Patients with only ventricular tachyarrhythmias had 690 documented episodes, 401 terminated spontaneously, 248 (85.8%) were terminated by ATP and 41 by shock.</AbstractText>Seventy-seven percent of patients with an ICD indication had spontaneous atrial and/or ventricular tachyharrhythmias within the first 6 months after ICD implantation. ATP therapy terminated 58% of all atrial tachyarrhytmias and 66.7% of the atrial flutters. The dual chamber ICD detected, classified and terminated all ventricular tacharrhythmias appropriately.</AbstractText>

Diagnostic approach to palpitations.

Palpitations-sensations of a rapid or irregular heartbeat-are most often caused by cardiac arrhythmias or anxiety. Most patients with arrhythmias do not complain of palpitations. However, any arrhythmia, including sinus tachycardia, atrial fibrillation, premature ventricular contractions, or ventricular tachycardia, can cause palpitations. Palpitations should be considered as potentially more serious if they are associated with dizziness, near-syncope, or syncope. Nonarrhythmic cardiac problems, such as mitral valve prolapse, pericarditis, and congestive heart failure, and noncardiac problems, such as hyperthyroidism, vasovagal syncope, and hypoglycemia, can cause palpitations. Palpitations also can result from stimulant drugs, and over-the-counter and prescription medications. No cause for the palpitations can be found in up to 16 percent of patients. Ambulatory electrocardiographic (ECG) monitoring usually is indicated if the etiology of palpitations cannot be determined from the patient's history, physical examination, and resting ECG. When palpitations occur unpredictably or do not occur daily, an initial two-week course of continuous closed-loop event recording is indicated. Holter monitoring for 24 to 48 hours may be appropriate in patients with daily palpitations. Trans-telephonic event monitors are more effective and cost-effective than Holter monitors for most patients.

[A study in cases of Brugada-type electrocardiogram and its management proposals in health examination].

In 1992, Brugada et al. reported a characteristic electrocardiogram (ECG) pattern and ST-segment elevation in leads V1 to V3 associated with sudden death in patients without demonstrable structural heart disease. That disease is now called Brugada Syndrome. The diagnostic criteria for the Brugada Syndrome have still not been decided on, and the prevalence of Brugada type ECG (B-ECG) varies widely in Japan. Therefore, we should consider B-ECG according to the consensus statement from the European Society of Cardiology and we proposed its management in health examinations. There were 35 B-ECG cases (0.9%), all male out of 3,875 Postal Service Trainees. There were 5 cases of Type I (Coved) (0.13%), 21 cases of Type II (0.54%), and 9 cases of Type III (0.23%), Only one case (0.026%) of Brugada Syndrome was found, and eventually, he received an Implantable Cardioverter Defibrillator (ICD). Type I (Coved) may be a more important electrocardiographic factor having a stronger causal relation to Ventricular Arrhythmia. Therefore, in management of health examinations, Type I patients with syncope or a family history of sudden cardiac death should visit a cardiologist for ICD-implantation, and even without any cardiac symptoms (syncope and a family history of sudden death), they are advised to visit a cardiologist for a program electrical stimulation (PES). Type II and III patients with any cardiac symptoms are advised to visit a cardiologist for PES or a drug challenge.

Extra-pleural pneumonectomy for malignant pleural mesothelioma: the risks of induction chemotherapy, right-sided procedures and prolonged operations.

With the increasing incidence of malignant pleural mesothelioma and renewed interest in radical surgery as a therapeutic option, we have examined our experience of extra-pleural pneumonectomy, to document the incidence and management of its peri-operative complications.</AbstractText>This analysis was conducted using prospectively entered data contained within the departmental database, with additional information from retrospective case note review. Details of patient selection criteria and operative modifications are included.</AbstractText>Over a 59-month period, extra-pleural pneumonectomy was carried out on 74 patients (66 men; 8 women; median age 57 years). Fifteen patients (20%) received cisplatin-doublet induction chemotherapy. The majority (80%) of patients had epithelial tumours and 85% of patients had disease in International Mesothelioma Interest Group stages III and IV. The 30-day post-operative mortality was 6.75% (five patients) and significant morbidity was recorded in 47 patients (63%). Major complications included those of technical origin (diaphragmatic patch dehiscence 8.1%; chylothorax 6.7%; intra-thoracic haemorrhage 6.7%; bronchopleural fistula 6.7%), cardiovascular morbidity (atrial fibrillation 17.5%; mediastinal shift with subacute tamponade 10.8%; right ventricular failure 4%; pulmonary embolus 2.7%) and respiratory morbidity (pneumonia 10.8%; acute lung injury 8.1%). Admission to intensive care was required in 19 patients (26%). Univariate analysis identified the incidence of acute lung injury and mediastinal shift to be significantly associated with induction chemotherapy (P=0.005 and 0.014, respectively). In addition to this, laterality of operation influenced respiratory morbidity (P=0.018) and admission to intensive care (P=0.025). Finally, prolonged operations (greater than the median) were associated with an increased risk of technical (P=0.018) and gastro-intestinal (P=0.023) complications.</AbstractText>Extra-pleural pneumonectomy is associated with a high rate of morbidity, but an acceptable mortality rate can be achieved with increasing peri-operative experience. Surgery following induction chemotherapy requires extra vigilance for the development of post-operative respiratory complications.</AbstractText>

Cardiac troponins in renal insufficiency and other non-ischemic cardiac conditions.

The emergence of cardiac troponins has been an interesting step in the diagnosis of ACS. It has clearly helped us to better triage patients toward a more aggressive posture in performing early cardiac catheterization, and in some cases, early use of adjunctive Gp IIb/IIIa antagonists and percutaneous or surgical myocardial revascularization. However, with this step forward has come uncertainty and many cardiology consults regarding positive cardiac troponins in patients without ACS or myocardial infarction. In general, increased cardiac troponins imply a worse prognosis. This is clearly true of patients with ESRD and advanced heart failure. It is also true of patients with severe, noncardiac illnesses. In other situations, such as acute pericarditis and cardiac surgery, slightly elevated cardiac troponins do not seem to predict a worse prognosis, and can probably be disregarded. The elevation of cardiac troponins after successful percutaneous coronary interventions is not unexpected, and the level of cardiac troponin release seems to predict problems, but lively controversy persists. Last, monitoring cardiac troponins in cardiac transplant recipients and those receiving certain cardiotoxic chemotherapies may be of some diagnostic value, but clearly more experience and clinical research are needed.

Long-term performance of prostheses in mitral valve replacement.

The long-term performance of prostheses in mitral valve replacement (MVR) is now available with representatives of current generation prostheses to 15 years. Mechanical prostheses have been implanted for 33 years and bioprostheses for 22 years. The predominant complication of mechanical prostheses is hemorrhage from anticoagulation and reoperation for late structural valve deterioration of bioprostheses. Mitral valve (MV) reconstruction, over MVR, is recommended whenever possible, especially with the advancement of atrial fibrillation ablation techniques. The current indications for MVR are those valvular lesions that are unlikely to be repaired by most surgeons or which long-term results are suboptimal with reconstruction. Reconstruction is more common for degenerative disease, replacement for rheumatic disease and variable for advanced ischemic and infective disease. The recommendations for MVR for mitral stenosis (MS) are moderate to severe MS with advanced functional status and severe pulmonary hypertension when percutaneous balloon valvotomy or mitral reconstruction is not feasible. MVR is recommended in non-ischemic severe mitral regurgitation (MR) and for non-reparable acute symptomatic MR, advanced symptomatic status, systolic dysfunction and/or ventricular dysfunction. The recommendations for MV surgery in ischemic MR are acute post-infarction MR with cardiogenic shock, unstable angina with persistent moderate-severe and severe MR and chronic, dilated ischemic cardiomyopathy with moderate-severe and severe MR.

A review of the pharmacokinetics, electrophysiology and clinical efficacy of dronedarone.

The results of major clinical trials and advances in pharmacologic and nonpharmacologic therapies are continuing to alter treatment approaches for both atrial and ventricular arrhythmias. Originally developed as an antianginal medication, amiodarone serves as the most effective antiarrhythmic drug in the treatment of both atrial and life-threatening ventricular arrhythmias. However, amiodarone has complex pharmacokinetics and is associated with serious extracardiac side effects, partially due to the presence of an iodine moiety. With a better understanding of the mechanisms of arrhythmias and antiarrhythmic drugs, new antiarrhythmic agents are currently under development with the hope that they will be more effective and safer than currently available drugs. One such drug that might potentially fulfill this hope is dronedarone. This amiodarone-like compound lacks the iodine moiety, and is similar in structure and electrophysiologic mechanisms of action to amiodarone, to date no evidence of liver, thyroid or pulmonary toxicity has been reported. Three clinical trials demonstrate efficacy in suppressing recurrences of atrial fibrillation and there is also evidence of a rate-slowing benefit during atrial fibrillation/flutter. However, the ANtiarrhythmic trial with DROnedarone in Moderate-to-severe congestive heart failure Evaluating morbidity Decrease (ANDROMEDA) study, performed in patients with left ventricular dysfunction, demonstrated excess noncardiac mortality in patients treated with dronedarone. Although effective in the treatment of atrial fibrillation, the future of this novel amiodarone-like drug remains uncertain until further clarification of the excess mortality in heart failure patients is better studied.

Better outcome after pediatric defibrillation dosage than adult dosage in a swine model of pediatric ventricular fibrillation.

This study was designed to compare outcome after adult defibrillation dosing versus pediatric dosing in a piglet model of prolonged prehospital ventricular fibrillation (VF).</AbstractText>Weight-based 2 to 4 J/kg monophasic defibrillation dosing is recommended for children in VF, but impractical for automated external defibrillator (AED) use. Present AEDs can only provide adult shock doses or newly developed attenuated adult doses intended for children. A single escalating energy sequence (50/75/86 J) of attenuated adult-dose biphasic shocks (pediatric dosing) is at least as effective as escalating monophasic weight-based dosing for prolonged VF in piglets, but this approach has not been compared to standard adult biphasic dosing.</AbstractText>Following 7 min of untreated VF, piglets weighing 13 to 26 kg (19 +/- 1 kg) received either biphasic 50/75/86 J (pediatric dose) or biphasic 200/300/360 J (adult dose) therapies during simulated prehospital life support.</AbstractText>Return of spontaneous circulation was attained in 15 of 16 pediatric-dose piglets and 14 of 16 adult-dose piglets. Four hours postresuscitation, pediatric dosing resulted in fewer elevations of cardiac troponin T (0 of 12 piglets vs. 6 of 11 piglets, p = 0.005) and less depression of left ventricular ejection fraction (p &lt; 0.05). Most importantly, more piglets survived to 24 h with good neurologic scores after pediatric shocks than adult shocks (13 of 16 piglets vs. 4 of 16 piglets, p = 0.004).</AbstractText>In this model, pediatric shocks resulted in superior outcome compared with adult shocks. These data suggest that adult defibrillation dosing may be harmful to pediatric patients with VF and support the use of attenuating electrodes with adult biphasic AEDs to defibrillate children.</AbstractText>

Angiotensin II receptor blockade reduces new-onset atrial fibrillation and subsequent stroke compared to atenolol: the Losartan Intervention For End Point Reduction in Hypertension (LIFE) study.

This study was designed to evaluate whether different antihypertensive treatment regimens with similar blood pressure reduction have different effects on new-onset atrial fibrillation (AF).</AbstractText>It is unknown whether angiotensin II receptor blockade is better than beta-blockade in preventing new-onset AF.</AbstractText>In the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study 9,193 hypertensive patients and patients with electrocardiogram-documented left ventricular hypertrophy were randomized to once-daily losartan- or atenolol-based antihypertensive therapy. Electrocardiograms were Minnesota coded centrally, and 8,851 patients without AF by electrocardiogram or history, who were thus at risk of developing AF, were followed for 4.8 +/- 1.0 years.</AbstractText>New-onset AF occurred in 150 patients randomized to losartan versus 221 to atenolol (6.8 vs. 10.1 per 1,000 person-years; relative risk 0.67, 95% confidence interval [CI] 0.55 to 0.83, p &lt; 0.001) despite similar blood pressure reduction. Patients receiving losartan tended to stay in sinus rhythm longer (1,809 +/- 225 vs. 1,709 +/- 254 days from baseline, p = 0.057) than those receiving atenolol. Moreover, patients with new-onset AF had two-, three- and fivefold increased rates, respectively, of cardiovascular events, stroke, and hospitalization for heart failure. There were fewer composite end points (n = 31 vs. 51, hazard ratio = 0.60, 95% CI 0.38 to 0.94, p = 0.03) and strokes (n = 19 vs. 38, hazard ratio = 0.49, 95% CI 0.29 to 0.86, p = 0.01) in patients who developed new-onset AF in the losartan compared to the atenolol treatment arm of the study. Furthermore, Cox regression analysis showed that losartan (21% risk reduction) and new-onset AF both independently predicted stroke even when adjusting for traditional risk factors.</AbstractText>Our novel finding is that new-onset AF and associated stroke were significantly reduced by losartan- compared to atenolol-based antihypertensive treatment with similar blood pressure reduction.</AbstractText>

Cardiovascular morbidity and mortality in hypertensive patients with a history of atrial fibrillation: The Losartan Intervention For End Point Reduction in Hypertension (LIFE) study.

We assessed the impact of antihypertensive treatment in hypertensive patients with electrocardiographic (ECG) left ventricular (LV) hypertrophy and a history of atrial fibrillation (AF).</AbstractText>Optimal treatment of hypertensive patients with AF to reduce the risk of cardiovascular morbidity and mortality remains unclear.</AbstractText>As part of the Losartan Intervention For End point reduction in hypertension (LIFE) study, 342 hypertensive patients with AF and LV hypertrophy were assigned to losartan- or atenolol-based therapy for 1,471 patient-years of follow-up.</AbstractText>The primary composite end point (cardiovascular mortality, stroke, and myocardial infarction) occurred in 36 patients in the losartan group versus 67 in the atenolol group (hazard ratio [HR] = 0.58, 95% confidence interval [CI] 0.39 to 0.88, p = 0.009). Cardiovascular deaths occurred in 20 versus 38 patients in the losartan and atenolol groups, respectively (HR = 0.58, 95% CI 0.33 to 0.99, p = 0.048). Stroke occurred in 18 versus 38 patients (HR = 0.55, 95% CI 0.31 to 0.97, p = 0.039), and myocardial infarction in 11 versus 8 patients (p = NS). Losartan-based treatment led to trends toward lower all-cause mortality (30 vs. 49, HR = 0.67, 95% CI 0.42 to 1.06, p = 0.090) and fewer pacemaker implantations (5 vs. 15, p = 0.065), whereas hospitalization for heart failure took place in 15 versus 26 patients and sudden cardiac death in 9 versus 17, respectively (both p = NS). The benefit of losartan was greater in patients with AF than those with sinus rhythm for the primary composite end point (p = 0.019) and cardiovascular mortality (p = 0.039).</AbstractText>Losartan is more effective than atenolol-based therapy in reducing the risk of the primary composite end point of cardiovascular morbidity and mortality as well as stroke and cardiovascular death in hypertensive patients with ECG LV hypertrophy and AF.</AbstractText>

P-wave signal-averaged electrocardiogram for predicting atrial arrhythmia after cardiac surgery.

Atrial arrhythmias (AF) are usually benign, but occur frequently after cardiac surgery. P-wave signal-averaged electrocardiogram has been used to characterize atrial conduction delay as a marker of risk of AF during sinus rhythm.</AbstractText>Ninety-five patients undergoing either primary isolated coronary artery bypass grafting or aortic valve replacement were enrolled. The duration and the root mean square voltage for the last 20 ms of filtered (40 to 300 Hz) P-wave of the spatial magnitude were recorded before surgery. Any episode of postoperative atrial fibrillation, atrial flutter, or paroxysmal atrial fibrillation lasting longer than 1 hour was considered as AF.</AbstractText>Twenty-eight patients (29%) exhibited AF 3.0 +/- 2.3 days after surgery. The P-wave duration recorded with P-wave signal-averaged electrocardiogram was significantly prolonged in patients with AF (135 +/- 14 ms versus 127 +/- 9 ms; p = 0.002). Patients with AF more often had dilated left atrium (p = 0.003), left ventricular hypertrophy (p = 0.03), and advanced age (p = 0.02). Logistic regression analysis identified the following three variables as predictive of AF: P-wave duration of 135 ms or greater (p = 0.02; odds ratio, 3.5), patients 70 years of age and older (p = 0.03; odds ratio, 3.2), and left atrial dimension of 35 mm or greater (p = 0.03; odds ratio, 3.2). If a patient had two or more of these three risk factors, the occurrence of AF was predicted with a sensitivity of 75%, specificity of 76%, positive predictive accuracy of 57%, and negative predictive accuracy of 88%.</AbstractText>The prolonged P-wave duration recorded with P-wave signal-averaged electrocardiogram, together with advanced age and left atrial enlargement, is a potent and independent predictor of AF after cardiac surgery. Patients with these risk factors may benefit from prophylactic antiarrhythmic treatment.</AbstractText>

Myocardial ischaemic preconditioning in the pig has no effect on the ventricular fibrillation and defibrillation thresholds.

The effects of myocardial ischaemia preconditioning in pigs on the vulnerability to ventricular fibrillation during subsequent ischaemic events are controversial. This study examined the time course of changes in ventricular fibrillation (VFT) and defibrillation (DFT) thresholds during transient myocardial ischaemia after a 45 min preconditioning period.</AbstractText>In five open-chest pigs, VFT was measured after 3 min of regional myocardial ischaemia, at time 0, 2, 15, 30, 60 and 90 min (Control group). In seven other pigs (Test group), VFT was measured before (time 0) and 2, 15, 30, 60 and 90 min after ischaemic preconditioning by three consecutive 5 min periods of regional coronary occlusion, followed by 10 min of reperfusion. DFT was measured by increasing the stored energy systematically until successful defibrillation. Ischaemic preconditioning caused no significant change in the effective refractory period (ERP), VFT or DFT over the 90 min of the experiments. In the Control group, ERP remained stable for 30 min, though was significantly lower at 90 min (178 +/- 28 ms) than at baseline (204 +/- 32 ms, P = 0.007). VFT and DFT remained unchanged throughout the experiments, and no difference was observed in ERP, VFT and DFT between the two groups at any time during the experiment.</AbstractText>No changes were observed in the refractory duration, ventricular vulnerability or defibrillation energy requirements up to 90 min after ventricular ischaemic preconditioning in the pig.</AbstractText>

Effects of incomplete chest wall decompression during cardiopulmonary resuscitation on coronary and cerebral perfusion pressures in a porcine model of cardiac arrest.

Recent data suggest that generation of negative intrathoracic pressure during the decompression phase of CPR improves hemodynamics, organ perfusion and survival.</AbstractText>Incomplete chest wall recoil during the decompression phase of standard CPR increases intrathoracic pressure and right atrial pressure, impedes venous return, decreases compression-induced aortic pressures and results in a decrease of mean arterial pressure, coronary and cerebral perfusion pressure.</AbstractText>Nine pigs in ventricular fibrillation (VF) for 6 min, were treated with an automated compression/decompression device with a compression rate of 100 min(-1), a depth of 25% of the anterior-posterior diameter, and a compression to ventilation ratio of 15:2 with 100% decompression (standard CPR) for 3 min. Compression was then reduced to 75% of complete decompression for 1 min of CPR and then restored for another 1 min of CPR to 100% full decompression. Coronary perfusion pressure (CPP) was calculated as the diastolic (aortic (Ao)-right atrial (RA) pressure). Cerebral perfusion pressure (CerPP) was calculated multiple ways: (1) the positive area (in mmHg s) between aortic pressure and intracranial pressure (ICP) waveforms, (2) the coincident difference in systolic and diastolic aortic and intracranial pressures (mmHg), and (3) CerPP = MAP--ICP. ANOVA was used for statistical analysis and all values were expressed as mean +/- S.E.M. The power of the study for an alpha level of significance set at 0.05 was &gt;0.90.</AbstractText>With CPR performed with 100%-75%-100% of complete chest wall recoil, respectively, the CPP was 23.3 +/- 1.9, 15.1 +/- 1.6, 16.6 +/- 1.9, p = 0.003; CerPP was: (1) area: 313.8 +/- 104, 89.2 +/- 39, 170.5 +/- 42.9, p = 0.03, (2) systolic aortic minus intracranial pressure difference: 22.8 +/- 3.6, 16.5 +/- 4, 23.7 +/- 4.5, p = n.s., and diastolic pressure difference: 5.7 +/- 3, -2.4 +/- 2.4, 3.2 +/- 2.5, p = 0.04 and (3) mean: 14.3 +/- 3, 7 +/- 2.9, 12.4 +/- 2.9, p = 0.03, diastolic aortic pressure was 28.1 +/- 2.5, 20.7 +/- 1.9, 20.9 +/- 2.1, p = 0.0125; ICP during decompression was 22.8 +/- 1.7, 23 +/- 1.5, 19.7 +/- 1.7, p = n.s. and mean ICP was 37.1 +/- 2.3, 35.5 +/- 2.2, 35.2 +/- 2.4, p = n.s.; RA diastolic pressure 4.8 +/- 1.3, 5.6 +/- 1.2, 4.3 +/- 1.2 p = 0.1; MAP was 52 +/- 2.9, 43.3 +/- 3, 48.3 +/- 2.9, p = 0.04; decompression endotracheal pressure, -0.7 +/- 0.1, -0.3 +/- 0.1, -0.75 +/- 0.1, p = 0.045.</AbstractText>Incomplete chest wall recoil during the decompression phase of CPR increases endotracheal pressure, impedes venous return and decreases mean arterial pressure, and coronary and cerebral perfusion pressures.</AbstractText>

The three-phase model of cardiac arrest as applied to ventricular fibrillation in a large, urban emergency medical services system.

Cardiac arrest is responsible for significant morbidity and mortality, with consistently poor outcomes despite the rapid availability of prehospital personnel for defibrillation attempts in patients with ventricular fibrillation (VF). Recent evidence suggests a period of cardiopulmonary resuscitation (CPR) prior to defibrillation attempts may improve outcomes in patients with moderate time since collapse (4-10 min).</AbstractText>To determine cardiac arrest outcomes in our community and explore the relationship between time since collapse, performance of bystander CPR, and survival.</AbstractText>Non-traumatic cardiac arrest data were collected prospectively over an 18-month period. Patients were excluded for: age &lt;18 years, a "Do Not Attempt Resuscitation" (DNAR) directive, determination of a non-cardiac etiology for arrest, and an initially recorded rhythm other than VF. Patients were stratified by time since collapse (&lt;4, 4-10, &gt; 10 min, and unknown) and compared with regard to survival and neurological outcome. In addition, patients with and without bystander CPR were compared with regard to survival.</AbstractText>: A total of 1141 adult non-traumatic cardiac arrest victims were identified over the 18-month study period. This included 272 patients with VF as the initially recorded rhythm. Of these, 185 had a suspected cardiac etiology for the arrest; survival to hospital discharge was 15% in this group, with 82% of these having a good outcome or only moderate disability. Survival was highest among patients with time since collapse of less than 4 min and decreased with increasing time since collapse. There were no survivors among patients with time since collapse greater than 10 min. Among patients with time since collapse of 4 min or longer, survival was significantly higher with the performance of bystander CPR; there was no survival advantage to bystander CPR among patients with time since collapse less than 4 min.</AbstractText>The performance of bystander CPR prior to defibrillation by EMS personnel is associated with improved survival among patients with time since collapse longer than 4 min but not less than 4 min. These data are consistent with the three-phase model of cardiac arrest.</AbstractText>

Post-shock chest compression delays with automated external defibrillator use.

In a swine model of out-of-hospital ventricular fibrillation (VF) cardiac arrest, we established that automated external defibrillator (AED) defibrillation could worsen outcome from prolonged VF compared with manual defibrillation. Worse outcomes were due to substantial interruptions and delays in chest compressions for AED rhythm analyses and shock advice. In particular, the mean interval from first AED shock to first post-shock compressions was 46+/-6s. We hypothesized that the delay from shock to provision of chest compressions is similar in the out-of-hospital setting.</AbstractText>We conducted a retrospective observational review of AED-treated adult VF cardiac arrest victims over a 26-month period to determine the interval from the first AED defibrillation attempt to the initial provision of post-shock chest compressions for out-of-hospital VF cardiac arrests. A two-tiered, single emergency medical service (EMS) system with AED-equipped first responders serves our area of 400 km2 with a population of 487,000 people. The defibrillators record a detailed sequence of events during the resuscitation effort that includes the electrocardiogram with real clock times and a recording of surrounding audible actions.</AbstractText>A median of 38 s (IQR 15, 61 s) elapsed between the first shock and the initiation of chest compressions. Approximately half of the delay was due to mechanical/electronic factors and the remainder due to human factors. Of 64 adults in VF, 45 (70%) died before hospital admission, 19 (30%) survived to admission and 10 (16%) survived to hospital discharge.</AbstractText>Substantial delays in the provision of post-shock chest compressions are typical in this EMS system with AED-equipped first responders.</AbstractText>

The Department of Health National Defibrillator Programme: analysis of downloads from 250 deployments of public access defibrillators.

From April 2000 to November 2002, the Department of Health (England) placed 681 automated external defibrillators (AEDs) in 110 public places for use by volunteer lay first responders. An audit has been undertaken of the first 250 deployments, of which 182 were for confirmed cardiac arrest. Of these, 177 were witnessed whilst 5 occurred in situations that were remote or initially inaccessible to the responders. The response interval between collapse and the initiation of CPR or AED placement was estimated to be 3-5 min in most cases. Ventricular fibrillation or rapid ventricular tachycardia (one case) was the first recorded rhythm in 146 cases (82%). In all, 44 of the 177 witnessed cases are known to have survived to hospital discharge (25%). Complete downloads are available for 173 witnessed cases and of these 140 were shocked: first-shock success, defined as termination of the fibrillatory waveform for 5 s or more, was achieved in 132 of them. When data quality permitted, the downloads were analysed with special reference to the numbers of compressions given and also to interruptions in compression sequences for ventilations, for rhythm analysis by the AED, for clinical checks, and for unexplained operator delays. The average rate of compressions during sequences was 120 min(-1), but because of interruptions, the actual number administered over a full minute from the first CPR prompt was a median of only 38. The speed of response by the lay first responders in relation to AED use was similar to that reported for healthcare professionals.

An alternative approach to advancing resuscitation science.

Stagnant survival rates in out-of-hospital cardiac arrest remain a great impetus for advancing resuscitation science. International resuscitation guidelines, with all their advantages for standardizing resuscitation therapeutic protocols, can be difficult to change. A formalized evidence-based process has been adopted by the International Liason Committee on Resuscitation (ILCOR) in formulating such guidelines. Currently, randomized clinical trials are considered optimal evidence, and very few major changes in the Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care are made without such. An alternative approach is to allow externally controlled clinical trials more weight in Guideline formulation and resuscitation protocol adoption. In Tucson, Arizona (USA), the Fire Department cardiac arrest database has revealed a number of resuscitation issues. These include a poor bystander CPR rate, a lack of response to initial defibrillation after prolonged ventricular fibrillation, and substantial time without chest compressions during the resuscitation effort. A local change in our previous resuscitation protocols had been instituted based upon this historical database information.

Clinical applications of B-type natriuretic peptide levels in the care of cardiovascular patients.

B-type natriuretic peptide (BNP), is a cardiac neurohormone, and is released as prepro BNP and then enzymatically cleaved to the N-terminal-proBNP and BNP upon ventricular myocyte stretch. Blood measurements of BNP have been used to identify patients with heart failure (HF). The BNP assay is currently used in diagnosis, prognosis, screening, and response to treatment for patients with HF. In general, a BNP level below 100 pg/mL excludes acutely decompensated HF and levels &gt; 500 pg/ml indicate decompensation. There are supportive data for using BNP to guide both inpatient and outpatient HF diagnosis and treatment. When BNP is elevated in acute coronary syndromes, pulmonary embolism, and sepsis, it implies that subclinical left ventricular dysfunction is present and a higher mortality rate can be expected. Elevated BNP levels before cardiac surgery are associated with higher rates of atrial fibrillation and death. After bypass surgery, as left ventricular function improves, the BNP level can be expected to fall. Lastly, in patients with aortic stenosis, aortic regurgitation, and mitral regurgitation, BNP elevates and is associated or may precede the development of symptoms and possibly can serve as a trigger for additional evaluation or intervention.

First report of supraventricular tachycardia after intravenous pulse methylprednisolone therapy, with a brief review of the literature.

The occurrence of supraventricular tachycardia after high-dose intravenous methylprednisolone pulse therapy (HIVMPT) in a patient with active rheumatoid arthritis is described for the first time. This case report further expands the range of arrhythmias that can occur with HIVMPT. Other arrhythmias previously reported to occur after HIVMPT include atrial fibrillation, atrial flutter, junctional rhythm, and ventricular tachycardia. To the best of our knowledge, supraventricular tachycardia has not been reported previously, although severe bradycardia, hypotension, asystole, cardiovascular collapse, and sudden death have been documented. A review of the literature indicates that these case reports not withstanding, HIVMPT is generally safe, and cardiovascular toxicity is rare. However, close supervision with repeated measurements of blood pressure, electrocardiogram, and blood electrolytes is mandatory during and immediately after HIVMPT, especially for patients with pre-existing cardiovascular disease, and the lowest effective dose of methylprednisolone should be infused at a slow rate.

[Patients history following artificial aortic valve and pacemaker implantation].

The follow-up of 22 patients (out of 31 patients after artificial aortic valve and pacemaker implantation between 1982 and 2001) have been evaluated. There were 15 men aged 30-76 (x=55) and 7 women aged 43-69 (x=59). Aortic valve replacement (AVR) was subsequently followed by pacemaker implantation (PI) after approximately 16 days. Indication for permanent stimulation were: atrio-ventricular complete block in 18 patients and atrial fibrillation with slow ventricular response in the remaining 4. There were implanted 15 devices of VVI type and 7 of VDD type. The duration of follow up was 9-196 (x=56) months. All these patients remained in good general state (II degree--19 patients or II/III degree--3 patients acc. to NYHA classification). In 21 out of 22 patients, atrioventricular conduction disturbances and bradyarrhythmia remained for the entire follow-up duration with permanent stimulation (VVI or VAT). In one patient the postoperative complete atrio-ventricular block disappeared during follow up, 24 months after AVR.</AbstractText>1. The main indication for PI after AVR was complete atrio-ventricular block, persisting 2-3 weeks after surgery, without accompanying atrial fibrillation. 2. In long term follow up after AVR and PI (VVI or VDD) the dominance of 100% capture ventricular pacing have been recorded in almost all cases, which holds the decision of early postoperative PI.</AbstractText>

[Atrial fibrillation in a long-term follow-up after mitral valve replacement].

The aim of the study was to analyse cardiac rhythm after mitral valve replacement and to define pre-operative predictive factors for persistence of atrial fibrillation.</AbstractText>The study group consisted of 76 consecutive pts (54 F, 22 M), mean age 54.8 +/- 8.2 (38-71) years in whom mitral valve replacement was performed due to mitral stenosis (15 pts), regurgitation (18 pts) or mixed lesion (43 pts). The prevalence of AF after the procedure was analysed with relation to age, gender and the following preoperative echocardiographic parameters: left atrial size, mitral valve area, mitral regurgitation, tricuspid regurgitation and left ventricular ejection fraction.</AbstractText>Chronic AF was present in 51 pts (67.1%) before the procedure and in 34 pts (44.7%) after 17.3 +/- 11.9 months (6-46) follow-up, p&lt;0.005. Patients with AF after operation had larger left atrium size (58.6 +/- 10.9 vs 51.3 +/- 10.1 mm, p&lt;0.005) and lower ejection fraction (53.8 +/- 7.9 vs. 59.9 +/-8.4%, p&lt;0.01) as compared with pts in sinus rhythm. Among 51 pts with preoperative chronic AF, 21 pts recovered to sinus rhythm (subgroup I) and 30 pts remained in AF (subgroup II) after operation. The only significant differences between subgroup I and II were: higher prevalence of mitral regurgitation (85.7 vs 60%, p&lt;0.05), larger mitral valve area (1.4 +/- 0.3 vs 1.1 +/- 0.6 cm2, p&lt;0.025) and higher ejection fraction (58.9 +/- 7.3 vs. 53.4 +/- 8.4%, p&lt;0.025) in subgroup I.</AbstractText>1. The prevalence of AF diminishes significantly after mitral valve replacement. 2. Patients with pure mitral stenosis are at higher risk of remaining in AF after operation. 3. Preoperative left atrial dimension and LV ejection fraction are the most important predictive parameters for persistence of AF.</AbstractText>

[Long-term results of valvular condition and clinical state in patients operated with the Senning method].

8 patients suffering transposition of the great arteries (d-TGA) aged from 8-17 years (mean 12.6 years) after Senning procedure performed were analyzed. Right atrium and right ventricle enlargement was detected in all patients. Small jet tricuspid valve regurgitation was confirmed in 5 patients, significant tricuspid valve insufficiency in 3 patients. 4 patients had presented with tricuspid valve, aorta valve and mitral valve insufficiency. In one patient insignificant pulmonary artery stenosis had been diagnosed. Chronic cardiac failure (NYHA III/IV) has been diagnosed in 2 patients, other patients from the analyzed group are in good clinical condition. All patients but 2 were diagnosed with arrhythmia using 24-hour Holter ECG. In 2 patients sinus node dysfunction was noted. Also supraventricular extrasystole, ventricular extrasystole, supraventricular tachycardia, ventricular salve, paroxysmal atrial fibrillation were described. No drug therapy in 4 patients is needed, one is treated with ACE-inhibitors, one with diuretic drugs. 2 patients suffering cardiac failure had been treated with 4 drugs, also temporary with intravenous dopamine. One death had been noted, caused by serious arrhythmia. One patient had been qualified for heart transplantation, there is no further data regarding this case. Senning procedure can be considered high risk for various problems, so patients who underwent this type of correction should be carefully observed.

[Clinical experience with aortic connector system].

From April to December 2002, 40 patients underwent coronary artery bypass grafting (CABG) using the St. Jude Medical (Minneapolis) Symmetry bypass system (aortic connector system: ACS). 59 proximal anastomoses (51 saphenous vein grafts, 8 radial artery grafts) were performed with the ACS. One saphenous vein graft occluded during operation. Postoperative evaluation of the anastomotic patency was carried out by angiography in 45 grafts. Five of the saphenous vein grafts were occluded (5/38). One patient who was shock state before operation presented with postoperative unconsciousness. Another patient died at 8th postoperative day caused by ventricular fibrillation. We conclude that the ACS produces a simple, quick way of performing the proximal anastomosis without the need for clamping the aorta, allows reducing risk of embolization by aortic manipulation. However, it is necessary to discuss sufficiently using the ACS, because the graft patency with the ACS is lower than with standard suturing technique.

Magnetic resonance imaging during untreated ventricular fibrillation reveals prompt right ventricular overdistention without left ventricular volume loss.

Most out-of-hospital ventricular fibrillation (VF) is prolonged (&gt;5 minutes), and defibrillation from prolonged VF typically results in asystole or pulseless electrical activity. Recent visual epicardial observations in an open-chest, open-pericardium model of swine VF indicate that blood flows from the high-pressure arterial system to the lower-pressure venous system during untreated VF, thereby overdistending the right ventricle and apparently decreasing left ventricular size. Therefore, inadequate left ventricular stroke volume after defibrillation from prolonged VF has been postulated as a major contributor to the development of pulseless rhythms.</AbstractText>Ventricular dimensions were determined by MRI for 30 minutes of untreated VF in a closed-chest, closed-pericardium model in 6 swine. Within 1 minute of untreated VF, mean right ventricular volume increased by 29% but did not increase thereafter. During the first 5 minutes of untreated VF, mean left ventricular volume increased by 34%. Between 20 and 30 minutes of VF, stone heart occurred as manifested by dramatic thickening of the myocardium and concomitant substantial decreases in left ventricular volume.</AbstractText>In this closed-chest swine model of VF, substantial right ventricular volume changes occurred early and did not result in smaller left ventricular volumes. The changes in ventricular volumes before the late development of stone heart do not explain why defibrillation from brief duration VF (&lt;5 minutes) typically results in a pulsatile rhythm with return of spontaneous circulation, whereas defibrillation from prolonged VF (5 to 15 minutes) does not.</AbstractText>

Pathomorphological peculiarities of coronary artery ectasias and their role in the pathogenesis of sudden cardiac death.

Polypositional postmortem contrast coronarography and pathomorphological analysis were used to study 400 cases of atherosclerotic, postinfarction, arrhythmogenic, and hypertensive heart. High incidence of sudden cardiac death was established in patients with coronary artery ectasia in atherosclerotic heart. In most cases, ectasias were observed in the anterior interventricular branch of the left coronary artery with dominant localization in the second and forth segments. Correlation was found between the maximum incidence of ectasia in the anterior interventricular branch of the left coronary artery and their maximal length, diameter, and bag-shaped appearance. We determined characteristic alterations in cardiac angioarchitectonics reflecting segmentary location of ectasia reflecting inadequacy of coronary circulation and myocardial ischemia leading to ventricular fibrillation and sudden cardiac death.

Recovery of N100 component of auditory event-related potentials and EEG after cardiac arrest during propofol sedation.

We report on the EEG monitoring of a patient who suffered an episode of postoperative ventricular fibrillation (VF) following coronary artery bypass grafting (CABG). VF initially caused a considerable suppression and slowing of the EEG. The recovery of cerebral function was evaluated by recording both EEG and auditory event related potentials (ERPs). Six hours after the episode of VF, when the patient was asleep but arousable to voice command, the N100 component of the auditory ERPs had recovered to the level measured before the operation, whereas the EEG was still very slow for that level of sedation. This may have been due to VF having less effect on the N100 component than on the background EEG. Our findings suggest that measuring evoked potentials may improve the evaluation of brain function after cardiac arrest.

Relation of initial resting ventricular rate to the ability to achieve and maintain normal sinus rhythm in patients with atrial fibrillation.

Rate-control and rhythm-control strategies in the management of atrial fibrillation (AF) have been shown to have similar effects on morbidity and mortality. Data are lacking as to whether specific electrocardiographic features of AF affect the ability to achieve rate or rhythm control. This study evaluated the relation between initial resting ventricular rate (IRVR) during AF and the subsequent achievement of rate control and rhythm control in the AFFIRM Study. The independent relations between IRVR and the achievement of rate and rhythm control were assessed using multivariate Cox's proportional hazards modeling. In addition, we evaluated whether IRVR was associated with major cardiovascular end points. IRVR was analyzed in 4,059 patients. IRVR was higher in women, smokers, patients who had a first episode of AF, and in patients who had preserved left ventricular systolic function but lower in patients who had coronary artery disease, hypertension, left atrial enlargement, and a qualifying episode of AF that lasted &gt;48 hours. A higher IRVR was independently associated with the achievement (p &lt;0.0001) and maintenance (p = 0.0002) of sinus rhythm, whereas the ability to achieve adequate rate control was independent of IRVR. A higher IRVR was associated with an increased risk of cardiovascular hospitalization (p &lt;0.0001). In the appropriate clinical setting, a rhythm-control strategy should be considered for patients who have a higher IRVR.

Drug-induced block of cardiac HERG potassium channels and development of torsade de pointes arrhythmias: the case of antipsychotics.

The prolongation of the cardiac repolarization process, a result of the blocking of the Human Ether-ago-go Related Gene potassium channel, is an undesired accessory property shared by many pharmacological classes of non-cardiovascular drugs. Often the delayed cardiac repolarization process can be identified by a prolongation of the QT interval of the electrocardiograph. In these conditions, premature action potentials can trigger a dangerous polymorphic ventricular tachyarrhythmia, known as torsade de pointes, which occasionally can result in lethal ventricular fibrillation. In this work, brief descriptions of the electrophysiological basis of torsade de pointes and of the several pharmacological classes of torsadogenic drugs are given. Attention is focused on antipsychotics, with a deeper overview on the experimental and clinical reports about their torsadogenic properties.

Dispersion of cardiac action potential duration and the initiation of re-entry: a computational study.

The initiation of re-entrant cardiac arrhythmias is associated with increased dispersion of repolarisation, but the details are difficult to investigate either experimentally or clinically. We used a computational model of cardiac tissue to study systematically the association between action potential duration (APD) dispersion and susceptibility to re-entry.</AbstractText>We simulated a 60 x 60 mm2 D sheet of cardiac ventricular tissue using the Luo-Rudy phase 1 model, with maximal conductance of the K+ channel gKmax set to 0.004 mS mm(-2). Within the central 40 x 40 mm region we introduced square regions with prolonged APD by reducing gKmax to between 0.001 and 0.003 mS mm(-2). We varied (i) the spatial scale of these regions, (ii) the magnitude of gKmax in these regions, and (iii) cell-to-cell coupling.</AbstractText>Changing spatial scale from 5 to 20 mm increased APD dispersion from 49 to 102 ms, and the susceptible window from 31 to 86 ms. Decreasing gKmax in regions with prolonged APD from 0.003 to 0.001 mS mm-2 increased APD dispersion from 22 to 70 ms, and the susceptible window from &lt;1 to 56 ms. Decreasing cell-to-cell coupling by changing the diffusion coefficient from 0.2 to 0.05 mm2 ms(-1) increased APD dispersion from 57 to 88 ms, and increased the susceptible window from 41 to 74 ms.</AbstractText>We found a close association between increased APD dispersion and susceptibility to re-entrant arrhythmias, when APD dispersion is increased by larger spatial scale of heterogeneity, greater electrophysiological heterogeneity, and weaker cell-to-cell coupling.</AbstractText>

Dissociation of membrane potential and intracellular calcium during ventricular fibrillation.

Membrane potential and intracellular calcium during VF.</AbstractText>The cardiac action potential (AP) and the intracellular Ca transient (CaT) are closely associated under normal physiological conditions, but not during ventricular fibrillation (VF). The purpose of this study was to determine whether this dissociation is directly related to the fast activation rate during VF.</AbstractText>We optically mapped AP and CaT simultaneously in nine isolated rabbit hearts. Pinacidil, a K(ATP) channel opener, was used to shorten the action potential duration (APD) in order to capture tissue at fast pacing rates or to induce ventricular tachycardia (VT) comparable to VF activation rates. Mutual information (MI) was used to calculate the degree of AP and CaT coupling. Pinacidil (40 microM) infusion significantly shortened APD. The CL of VF without pinacidil averaged 77+/-13 ms, whereas the shortest CL achieved during VT under pinacidil infusion was 76 ms. MIs during fast pacing (1.13+/-0.15 bits) and fast VT (0.88+/-0.18 bits) were higher than those during baseline VF (0.39+/-0.11 bits), VF with pinacidil infusion (0.21+/-0.07 bits) and VF after pinacidil washout (0.36+/-0.15 bits). MIs during fast pacing or fast VT were higher than that of VFs at comparable dominant frequencies.</AbstractText>CaT is closely associated with the AP during fast pacing and fast VT, but not during VF. The reduced MI during VF is not secondary to the fast rate of activation.</AbstractText>

Numerical simulation of paced electrogram fractionation: relating clinical observations to changes in fibrosis and action potential duration.

Simulating paced electrogram fractionation.</AbstractText>Paced electrogram fractionation analysis (PEFA) may identify a re-entrant substrate in patients at risk of ventricular fibrillation (VF) by detecting prolonged, fractionated ventricular electrograms ("fractionation") in response to premature extrastimuli. Numerical simulations of action potential (AP) propagation through human myocardium following such premature stimulation were performed to study the relationship between electrogram fractionation, fibrosis, and changes in AP currents.</AbstractText>Activation in a resistive monodomain 2 cm2 sheet of myocardium containing nonconducting fibrous tissue was modeled using standard numerical methods for solutions of partial differential equations using the Priebe-Beukelmann (PB) AP equations. Myocardial fibrosis significantly influenced electrogram morphology. High densities of closely spaced fibrous septa caused functional block and altered propagation paths at short coupling intervals, and produced large increases in electrogram duration similar to those associated with increased risk of VF in clinical studies. Prolongation of the cardiac AP using the heart failure variant of the PB model further increased the amount of fractionation and thereby replicated clinical recordings more closely than did fibrosis alone. Increasing AP dispersion by a variable reduction in the potassium current I(Kr) simulated results seen in patients with the long QT syndrome with an abrupt increase in electrogram duration, while a uniform reduction in I(Kr) alone did not result in fractionated electrograms. In contrast, increases in cytosolic Ca2+ and Ca2+ buffering by troponin to simulate HCM had little effect on fractionation.</AbstractText>These results relate the effects of fibrosis, AP abnormalities, and dispersion of AP duration to the characteristic electrograms recorded in patients at risk of sudden death.</AbstractText>

Electrophysiological and histopathological characteristics of progressive atrioventricular block accompanied by familial dilated cardiomyopathy caused by a novel mutation of lamin A/C gene.

Conduction defect caused by lamin A/C gene mutation.</AbstractText>Mutations of lamin A/C gene (LMNA) cause dilated cardiomyopathy (DCM) with atrioventricular (AV) conduction defect, although the electrophysiological and histological profiles are not fully understood.</AbstractText>We analyzed a large Japanese family (21 affected and 203 unaffected members) of DCM with AV block. The responsible LMNA mutation of IVS3-10A&gt;G was novel and caused an aberrant splicing. The first clinical manifestation was low-grade AV block or atrial fibrillation (AF), which developed in affected members aged &gt;or=30 years. We observed that the AV block progressed to third-degree within several years. The electrophysiological study of the four affected members revealed an impairment of intra-AV nodal conduction. Because of advanced AV block, pacemakers were implanted in 14 out of 21 affected members at the mean age of 44 years. Three affected members died suddenly and two affected members died of heart failure and/or ventricular tachycardia (VT) even after the pacemaker implantation. Postmortem examination showed conspicuous fibrofatty degeneration of the AV node. Endomyocardial biopsies showed remarkably deformed nuclei and substantial glycogen deposits in the subsarcolemma.</AbstractText>The clinical phenotype in this family was characterized by (1) the first manifestation of the prolonged PQ interval or AF in adolescence, (2) progressive intra-AV nodal block to the third degree in several years, and (3) progressive heart failure after pacemaker implantation. Histological study revealed preferential degeneration at the AV node area and novel cellular damages in the working myocardium.</AbstractText>

Azimilide, a novel oral class III antiarrhythmic for both supraventricular and ventricular arrhythmias.

Azimilide is an investigational Class III antiarrhythmic that has been developed for treating both supraventricular and ventricular tachyarrhythmias. Similar to other Class III antiarrhythmics, azimilide prolongs myocardial repolarization in a dose-dependent manner by increasing the action potential duration, QT interval, and effective refractory period. The most frequent reported side effect is headache, with rare serious adverse events of early reversible neutropenia and Torsades de Pointes. In long-term follow up, the patient withdrawal rate has been low. Azimilide has very predictable pharmacokinetics, is predominantly hepatically metabolized, and has no significant drug interactions with digoxin or warfarin. In animal models, azimilide has been shown to be very effective in suppressing both atrial and ventricular tachyarrhythmias, decreasing the defibrillation energy requirement, and preventing post-myocardial infarction ventricular tachycardia and fibrillation. Clinically, in a series of 4 double-blind, randomized, placebo-controlled trials, the Azimilide Supraventricular Arrhythmia Program which included over 1000 patients and approximately 70% with structural heart disease, azimilide showed a significant prolongation in the time to first recurrence of paroxysmal supraventricular tachycardia or atrial fibrillation/flutter. With respect to ventricular tachyarrhythmias, the AzimiLide post-Infarct surVival Evaluation Trial was a large randomized, multinational, prospective, placebo-controlled study in recent survivors of myocardial infarction at high risk for sudden cardiac death. After 1 year of follow-up, this study showed no statistical difference in all-cause mortality between placebo and azimilide. However, azimilide did statistically reduce the incidence of new atrial fibrillation. Further trials are necessary to evaluate the efficacy of azimilide in patients with symptomatic ventricular arrhythmias.

[Biphasic shock waveform for cardioversion of atrial fibrillation in the emergency room].

Transthoracic electrical cardioversion, traditionally monophasic shock waveform, has been a mainstay of the therapy for atrial fibrillation (AF) since its introduction into clinical practice. Recent studies have demonstrated that biphasic shock is more efficient than monophasic shock waveforms for terminating both ventricular fibrillation and AF; however, data on the recommended initial shock energy in conversion of AF by biphasic shocks are limited.</AbstractText>Our study aimed to evaluate the optimal dose of the initial shock energy for conversion of AF to sinus rhythm by transthoracic biphasic shock waveforms in the Emergency Room (ER).</AbstractText>A total of 144 consecutive patients, who came to the ER because of AF, were our study population. All patients underwent cardioversion via anterior-laterally positioned hand-held electrode paddles. Patients received sequential shocks of 50 J (only the first 40 patients), 100 J, 150 J and 200 J if necessary. There was a significantly greater cumulative conversion success rate with 100 J (70.5%) than 50 J shock energy (55%), p &lt; 0.05; but even greater with 150 J (89%) than 100 J shock energy, p &lt; 0.003; no significant difference was observed between 200 J (94%) and 150 J shock energy, p &lt; 0.58. Nine of 12 patients, whose body weight was less than 70 kg, were successfully converted to sinus rhythm (75%) by 50 J shock 1 energy. After cardioversion there were reports of: a five seconds asystole observed in 1 patient; pulmonary edema in another patient; hypotension was reported in 1 patient and mild erythema in 14 patients (9.7%).</AbstractText>Our findings support that biphasic waveform shock energy of 150 J is advised as a first attempt, but in patients with a body weight less than 70 kg. lower energy shock may be used.</AbstractText>

[Marijuana smoking and paroxysmal atrial fibrillation].

Cannabis is the most widely used illegal drug in Israel, and unlike most of the other illegal drugs, it is common among segments of the population with higher demographic characteristics.</AbstractText>A healthy 20 year old male patient, with two previous admissions with atrial fibrillation, was admitted to the emergency room with paroxysmal atrial fibrillation. The patient presented evidence of cannabis abuse, and no other pathologic cause for atrial fibrillation. Sinus rhythm was restored and the patient was discharged.</AbstractText>Cannabis abuse is responsible for a wide range of pathologies, including cognitive impairment, a rise in the prevalence of lung, head and neck tumors, atrial and ventricular arrhythmias, and an increase in the risk of ischemic cardiovascular events.</AbstractText>Cannabis abuse can induce atrial fibrillation in predisposed patients. Good practice may consider the inclusion of cannabis abuse tests in young patients admitted due to atrial fibrillation, and definite medical advice to stop the drug abuse.</AbstractText>

Prevalence of and risk factors for atrial fibrillation in Korean adults older than 40 years.

Atrial fibrillation (AF) is a common arrhythmia that is a potent independent risk factor for stroke. The incidence of AF increase with age and most affected people have underlying cardiac disease. This study aimed to describe the prevalence of and risk factors for AF in Korean. In this study, 14,540 adults (male 6,573/female 7,967) &gt; or =40 yr old received screening test for general health between April 2000 and December 2000. Participants answered questionnaires and underwent examinations that included blood pressure, electrocardiogram (ECG), total cholesterol, and fasting glucose. Data analysis was done by SPSS 10.0 for Windows. The prevalence of AF was 0.7% in people older than 40 yr and 2.1% in those older than 65 yr. The prevalence in men was 1.2% and women was 0.4% in people older than 40 yr. The prevalence in men was 3.3% and women was 1.1% in people older than 65 yr. Approximately 56.6% of individuals with AF are older than 65 yr. The prevalence of AF was higher at all age group in men than in women. Also, the prevalence of AF was highest in people older than 80 yr. In univariate analysis, male sex, old age (&gt; or =65 yr), hypertension, diabetes mellitus, left ventricular hypertrophy in ECG, stroke, and cardiac disease were associated with an increased risk of AF. In multivariate analysis, however, risk factors of AF were male (odds ratio, OR 4.1; 95% confidence interval [CI] : 2.6 to 6.5; p=0.000), old age (OR 5.3; 95% CI:3.5 to 7.9; p=0.000), and cardiac disease (OR 19.8; 95% CI:12.3 to 31.8; p=0.000). In this study, the most potent risk factors of AF was cardiac disease.

New parameters for left ventricular function in atrial fibrillation: based on the relationship between RR interval and performance.

This study was designed to obtain new parameters representing left ventricular (LV) function independent of irregular RR intervals in atrial fibrillation (AF). AF patients were divided into Normal (n=9) and LV Dysfunction (n=9) groups. The relations between LV outflow peak ejection velocity (Vpe) and preceding (RR-1) or prepreceding RR intervals (RR-2) were obtained using logarithmic equations, from which the squared correlation coefficient (r2), slope, Vpe at RR-1 or RR-2=1 sec (Vpe-1), and the ratio of slope to Vpe-1 (Slope/Vpe-1) were calculated. Among the parameters between RR-1 and Vpe, Slope/Vpe-1 was higher in LV Dysfunction group than in Normal group (p=0.05). When only coordinates with RR-1 from 0.6 to 1 sec were included, Slope/Vpe-1 (p=0.001) was higher in LV Dysfunction group than in Normal group. Among the parameters between RR-2 and Vpe, Slope/Vpe-1, slope, and r2 were different between the two groups. In multivariate analysis, Slope/Vpe-1 between RR-2 and Vpe was only independent parameter. However, Slope/Vpe-1 between RR-1 and Vpe in the coordinates with RR-1 from 0.6 to 1 sec had the highest discriminating power. New parameters derived from the relations between RR intervals and LV performance might be useful to evaluate LV function quantitatively in AF.

Difference in survival after out-of-hospital cardiac arrest between the two largest cities in Sweden: a matter of time?

Dramatic differences in survival after out-of-hospital cardiac arrests (OHCA) reported from different geographical locations require analysis. We therefore compared patients with OHCA in the two largest cities in Sweden with regard to various factors at resuscitation and outcome.</AbstractText>All patients suffering an OHCA in Stockholm and Goteborg between 1 January 2000 and 30 June 2001, in whom cardiopulmonary resuscitation (CPR) was attempted were included in this retrospective analysis.</AbstractText>All together, 969 OHCA in Stockholm and 398 in Goteborg were registered during the 18-month study period. There were no differences in terms of age, gender, and percentage of witnessed cases or percentage of patients who had received bystander CPR. However, the percentage of patients with ventricular fibrillation (VF) at arrival of the ambulance crew was 18% in Stockholm versus 31% in Goteborg (P &lt;0.0001). The percentage of patients who were alive 1 month after cardiac arrest was 2.5% in Stockholm versus 6.8% in Goteborg (P=0.0008). Various time intervals such as cardiac arrest to calling for an ambulance, cardiac arrest to the start of CPR and calling for an ambulance to its arrival were all significantly longer in Stockholm than in Goteborg.</AbstractText>Survival was almost three times higher in Goteborg than in Stockholm amongst patients suffering an OHCA. This is primarily explained by a higher occurrence of VF at the time of arrival of the ambulance crew, which in turn probably is explained by shorter delays in Goteborg. The reason for the difference in time intervals is most likely multifactorial, with a significantly higher ambulance density in Goteborg as one possible explanation.</AbstractText>

Relationship of QT interval duration with carotid intima media thickness in a clinically healthy population undergoing cardiovascular risk screening.

To investigate the relationship between cardiac repolarization (QT interval duration) and intima media thickness (IMT) of the carotid arteries as surrogate measures of subclinical atherosclerosis.</AbstractText>Prospective study with consecutive subjects enrolled in the SAPHIR program (Salzburg Atherosclerosis Prevention Program in Subjects at High Individual Risk).</AbstractText>The analysis of the material was performed at the departments of medicine and neurology of a university hospital.</AbstractText>The study cohort comprises a population-based sample of 1199 clinically healthy subjects (851 men and 348 women; age 39-66 years). Exclusion criteria were cardiovascular disease, diabetes, atrial fibrillation, bundle branch block and use of medication affecting QT interval duration.</AbstractText>IMT of common (CCA) and internal carotid arteries (ICA) was measured by B-mode ultrasound. QT interval duration was determined in the resting 12-lead electrocardiogram by an automatic analysis program. The QT intervals were corrected for heart rate with five standard equations (QTc-Bazett, -Fridericia, -Framingham, -Hodges and -Rautaharju) and tested for their relationship with carotid IMT after adjustment for clinical and metabolic variables. Results. Females had higher heart rates than males (64 +/- 10 b min(-1) vs. 60 +/- 9 b min(-1), P &lt;0.0005), with longer mean QT (410 +/- 28 ms vs. 404 +/- 28 ms, P=0.003) and QTc intervals in all correction formulae (P &lt;0.0005). Significant correlations between QT/QTc and ICA IMT (r=0.14-0.16) were found in males. In the general linear model the association between QTc (except for Bazett) and ICA IMT remained significant after adjusting for age, BMI and further cardiovascular risk factors. In females the crude correlations between QT/QTc and ICA IMT were lower than those with CCA IMT. Only the correlation between uncorrected QT and CCA IMT (r=0.15, P=0.006) remained significant after adjustment for covariates.</AbstractText>The results of the present study demonstrate that QT and QTc prolongation are in part associated with IMT of carotid arteries, which is an established risk marker of subclinical atherosclerosis. In men the data support the hypothesis of an association between QTc and ICA IMT. In women a statistically significant relationship was found between the uncorrected QT interval and CCA IMT. These findings suggest that differences in carotid IMT and ventricular repolarization between genders might be related to hormonal and nonhormonal effects.</AbstractText>

Cold injuries.

Exposure to cold can produce a variety of injuries that occur as a result of man's inability to adapt to cold. These injuries can be divided into localized injury to a body part, systemic hypothermia, or a combination of both. Body temperature may fall as a result of heat loss by radiation, evaporation, conduction, and convection. Hypothermia or systemic cold injury occurs when the core body temperature has decreased to 35 degrees C (95 degrees F) or less. The causes of hypothermia are either primary or secondary. Primary, or accidental, hypothermia occurs in healthy individuals inadequately clothed and exposed to severe cooling. In secondary hypothermia, another illness predisposes the individual to accidental hypothermia. Hypothermia affects multiple organs with symptoms of hypothermia that vary according to the severity of cold injury. The diagnosis of hypothermia is easy if the patient is a mountaineer who is stranded in cold weather. However, it may be more difficult in an elderly patient who has been exposed to a cold environment. In either case, the rectal temperature should be checked with a low-reading thermometer. The general principals of prehospital management are to (1) prevent further heat loss, (2) rewarm the body core temperature in advance of the shell, and (3) avoid precipitating ventricular fibrillation. There are two general techniques of rewarming--passive and active. The mechanisms of peripheral cold injury can be divided into phenomena that affect cells and extracellular fluids (direct effects) and those that disrupt the function of the organized tissue and the integrity of the circulation (indirect effects). Generally, no serious damage is seen until tissue freezing occurs. The mildest form of peripheral cold injury is frostnip. Chilblains represent a more severe form of cold injury than frostnip and occur after exposure to nonfreezing temperatures and damp conditions. Immersion (trench) foot, a disease of the sympathetic nerves and blood vessels in the feet, is observed in shipwreck survivors or in soldiers whose feet have been wet, but not freezing, for long periods. Patients with frostbite frequently present with multisystem injuries (e.g., systemic hypothermia, blunt trauma, substance abuse). The freezing of the corneas has been reported to occur in individuals who keep their eyes open in high wind-chill situations without protective goggles (e.g., snowmobilers, cross-country skiers).

[Pharmacological treatment of atrial fibrillation].

Although anticoagulant treatment of atrial fibrillation is now well codified, the medical treatment of the fibrillation remains controversial. Two types of medication can be proposed: drugs to slow the rhythm (digitalis, betablockers and calcium inhibitors) and anti-arrhythmic mainly Class I or Class III drugs. Some doubt was raised in the 1990's about the pertinence of antiarrhythmic therapy and four recent trials (AFFIRM, RACE, PIAF and STAF) compared the two attitudes of "rhythm control" or "rate control" in atrial fibrillation. The four trials all showed that the results of these two options were equivalent with respect to the therapeutic objectives: reduction of mortality, thromboembolic or haemodynamic risk, and regression of symptoms and improvement of the quality of life. However, these trials have not closed the debate on these two therapeutic attitudes. In fact, analysis shows that the comparison was biased because anticoagulant treatment was inadequate and, though the treatment for rate control was appropriate, the antiarrhythmic treatment was far from being satisfactory and effective. Moreover, many patients in the "rhythm control" group were in atrial fibrillation whereas a certain number of patients in the "rate control" group were, in fact, in sinus rhythm throughout the study period. In addition, the comparison was incomplete because it did not include two other particularly common populations in clinical practice: multi-relapsing paroxysmal atrial fibrillation in healthy hearts and atrial fibrillation associated with severe left ventricular dysfunction, patients with cardiac failure. Until the results of trials currently under way (AF-CHF) become available, the authors discuss the use of drugs for rate control and antiarrhythmic therapy in everyday practice.

[The choice of pacing sites: should we change our practice?].

For the past 45 years the sites used for elective pacing have been the apex of the right ventricle and the right atrium. Although the initial objective of pacing was the "simple" correction of a conduction disorder, a more recent evolution has been to achieve a favourable haemodynamic effect, considering left ventricular filling and synchronisation of ventricular contraction as essential. Demonstration of the benefit in terms of survival brought about by pacing in atrioventricular block has not required large trials. However, it is possible that this improvement in morbidity and mortality is in part offset by the altered haemodynamics due to pacing at the right ventricular apex. At the atrial level, the prevention of AF is the holy grail of atrial pacing, but is far from being attained, perhaps because the physiopathological bases are not clear and have not really been demonstrated, casting doubt on the final objective. The choice of pacing site is essential in this context, as much in the atrium as in the ventricle. The current problem regarding this choice is the same as for all medical treatment, where the risk/benefit ratio is evaluated: if the usual sites are potentially deleterious, is it possible to continue using them or is it necessary to change implantation practices, and what level of proof is needed?

[The best of cardiac pacing in 2004].

The year 2004 saw the publication of the results of the COMPANION and PAVE studies concerning cardiac pacing. The former underlined, if it was still necessary, the direct relationship between pacing and rhythmology in terms of sudden death due to rhythm disturbances in cardiac failure. COMPANION attempted to discover whether, in severe cardiac failure with intraventricular conduction defects, the addition of multisite pacing either with or without defibrillation is liable to alter the combined risk of death and hospital episodes compared with optimal drug therapy alone. This study confirmed the advantages of resynchronisation pacing already observed in MUSTIC, MIRACLE, InSync and CONTAK CD: retarded progression of cardiac failure, reduction in the number of hospitalisations and functional improvement. Adding defibrillation to anti-bradycardial resynchronisation pacing improved the survival, but only slightly so. On the other hand, the size of the subgroups did not allow any conclusions to be drawn about function and aetiology of cardiac failure, whether ischaemic or not. The PAVE study allowed comparison between biventricular pacing and right ventricular pacing alone in patients in NYHA class II or III, with atrial fibrillation for more than one month and having undergone elective ablation of the nodo-Hissian pathway. The results gave confirmation of the harmful effects of pacing at the apex of the right ventricle in pacing-dependent patients. On the technological front, there was confirmation that probes designed for left ventricular stimulation are stable and increasingly easy to use thanks to a new configuration and the use of bipolar. Finally, telecardiology has started to proliferate and evaluation of its applications is under way, even though its clinical use is confirmed on a daily basis.

[The best of arrhythmia in 2004].

As for the preceding years, important studies regarding several remaining clinical issues for electrophysiologists have been reported in 2004. Large randomized studies have underlined the need for an EP study in asymptomatic patients with overt ventricular preexcitation. In addition to a short antegrade refractory period, arrhythmia induction (atrial fibrillation or reciprocating tachycardia) argues for accessory pathway ablation. Although currently leading to fairly good results, atrial fibrillation ablation technique is still evolving. Encircling pulmonary vein and the surrounding atrial tissue seems to give better long term clinical results as compared to ostial pulmonary vein disconnection. Large series have confirmed that whatever cardiomyopathy etiology, prophylactic ICD implantation was associated with a reduction of sudden arrhythmic death during follow-up in patients with low ejection fraction. However, in order to save one patient more and more patients have to be implanted because of the increasing efficacy of pharmacological treatment for heart failure. Three clinical series of arrhythmogenic right ventricular dysplasia implanted with AICD have been published this year. The prognostic factors for the occurrence of severe ventricular arrhythmia are hemodynamically ill tolerated ventricular tachycardia, and VT induction during EP study. Management of patients with Brugada syndrome is still far from being well defined. Interestingly in a recent report, hydroquinidine has been found to reduce the incidence of ventricular arrhythmia in the follow-up as well as the rate of ventricular arrhythmia induction in the EP lab. Yet, prophylactic ICD implantation remains the treatment of choice in symptomatic and inducible patients.

Conscious sedation during endoscopic retrograde colangiopancreatography: implementation of SIED-SIAARTI-ANOTE guidelines in Belluno Hospital.

In this study we describe the results of adoption of local guidelines for conscious sedation (CS) during endoscopic-retrograde-cholangiopancreatography (ERCP) in Belluno Hospital. Local guidelines were created referring to SIED-SIAARTI-ANOTE guidelines for CS in gastrointestinal endoscopy.</AbstractText>Between January 2002 and February 2004, 300 ERCPs to be performed under CS have been scheduled. According to local guidelines CS was performed by the gastroenterologist assisted by an anesthesia nurse. An anesthesiologist was always on call in the intensive care unit (ICU) for emergencies and could be on the site in less than 5 min.</AbstractText>In 278 patients the procedure was performed safely and effectively by the gastroenterologist without any anesthesiological assistance. At follow-up controls patients had either positive or no recollection of the procedure. An anesthesiologist was called in 13 cases to perform deep sedation and in 9 cases to deal with undesired effects (arterial hypertension in 5 patients, 1 episode of bradycardia, 1 of ventricular tachycardia, 1 of atrial fibrillation and 1 of hypoxia).</AbstractText>In our experience, CS during ERCP can be safely performed autonomously by a gastroenterologist in the majority of cases. Drug prescription protocol and the presence of an anesthesia nurse create ideal conditions for the operator, patient comfort and good results with a low incidence of undesired events and few calls for the anesthesiologist. To allow safe and effective performance of CS, the Department of Anesthesia should promote the in-service training and up dating of gastroenterologists and anesthesia nurses.</AbstractText>

Rate vs rhythm control in patients with atrial fibrillation: a meta-analysis.

The 2 fundamental approaches to the management of atrial fibrillation (AF) are reestablishing and maintaining sinus rhythm (rhythm control) and controlling ventricular rate with atrioventricular node blocking agents (rate control). We performed a meta-analysis of randomized controlled trials comparing these strategies in patients with AF to add precision to the relative merits of both strategies on the risk of all-cause mortality and to evaluate the consistency of the results between trials.</AbstractText>We performed a literature search in MEDLINE (1966 to May 2003), the Cochrane Controlled Trial Registry (first quarter of 2003), and International Pharmaceutical Abstracts (1970 to May 2003). Eligible trials were randomized controlled trials comparing pharmacologic rhythm and rate control strategies as first-line therapy in patients with AF.</AbstractText>Five trials were identified that included a total of 5,239 patients with persistent AF or AF that was considered likely to be recurrent. No significant difference was observed between the rate and the rhythm control groups regarding all-cause mortality, although a strong trend in favor of a rate control approach was observed (13.0% vs 14.6%; odds ratio, 0.87; 95% confidence interval, 0.74-1.02; P=.09). No heterogeneity was apparent between the trials (Q value=2.97; P=.56).</AbstractText>In patients with persistent AF or with AF that is likely to be recurrent, a strategy of ventricular rate control, in combination with anticoagulation in appropriate patients, appears to be at least equivalent to a strategy of maintaining sinus rhythm by using currently available antiarrhythmic drugs in preventing clinical outcomes.</AbstractText>

Spatiotemporal blind source separation approach to atrial activity estimation in atrial tachyarrhythmias.

The analysis and characterization of atrial tachyarrhythmias requires, in a previous step, the extraction of the atrial activity (AA) free from ventricular activity and other artefacts. This contribution adopts the blind source separation (BSS) approach to AA estimation from multilead electrocardiograms (ECGs). Previously proposed BSS methods for AA extraction--e.g., independent component analysis (ICA)--exploit only the spatial diversity introduced by the multiple spatially-separated electrodes. However, AA typically shows certain degree of temporal correlation, with a narrowband spectrum featuring a main frequency peak around 3.5-9 Hz. Taking advantage of this observation, we put forward a novel two-step BSS-based technique which exploits both spatial and temporal information contained in the recorded ECG signals. The spatiotemporal BSS algorithm is validated on simulated and real ECGs from a significant number of atrial fibrillation (AF) and atrial flutter (AFL) episodes, and proves consistently superior to a spatial-only ICA method. In simulated ECGs, a new methodology for the synthetic generation of realistic AF episodes is proposed, which includes a judicious comparison between the known AA content and the estimated AA sources. Using this methodology, the ICA technique obtains correlation indexes of 0.751, whereas the proposed approach obtains a correlation of 0.830 and an error in the estimated signal reduced by a factor of 40%. In real ECG recordings, we propose to measure performance by the spectral concentration (SC) around the main frequency peak. The spatiotemporal algorithm outperforms the ICA method, obtaining a SC of 58.8% and 44.7%, respectively.

[Sudden death due to electrical causes in individuals without demonstrable structural cardiac disease. Experience in Cuba].

Sudden cardiac death due to electrical causes in individuals with no evidence of structural heart disease is an important clinical and public health problem, and it is not yet solved. The objectives of this study were: to characterize patients reanimated from a sudden death event of electrical cause; to know the mediated evolution during a period of three years and to study premonitory electrical signs. 42 individuals were studied, 30 were male and 12 female, mean age 37.7 years, healthy heart, by clinic and paraclinic methods. Nine subpopulations were studied, being Brugada syndrome, long QT syndrome and idiopathic ventricular fibrillation the most frequent. Ventricular fibrillation and twisting of the points were the arrhythmias responsible for most death events. There were premonitory signs in 92.8% and clinical recurrences of life-threatening events in 71.4% but they were induced during programmed electrical stimulation only in 4 of 18 patients. Atrial fibrillation was the most frequent coexistent arrhythmia (19%). In summary, there are frequent premonitory signs (particularly atrial fibrillation), and also malignant arrhythmic recurrences but a poor inducibility at the electrophysiology laboratory. It is very difficult to stratify the risk because of the low predictive value of diagnostic methods.

[Pulmonary artery catheterization in 9071 cardiac surgery patients: a review of complications].

The safety of pulmonary artery catheterization has been questioned. We report our experience on the incidence of complications in a large series of patients requiring cardiac operations by evaluating the learning curve of the operators.</AbstractText>Since 1988 at our Institution a pulmonary artery catheter (PAC) register records the following data from each patient: type of surgical procedure, insertion site of the venous introducer, type of PAC used, final position of the catheter, and complications associated with central venous access and those determined by PAC positioning and stay. During 16 years (from April 1988 to April 2004) 9071 PACs were registered.</AbstractText>Complications associated with the access to the central venous pool consisted of carotid arterial puncture in 191 patients (2.1%) and pneumothorax in 4 patients (0.04%). Complications associated with PAC positioning consisted of runs of ventricular ectopic beats (&gt; 6 s) in 62 patients (0.68%), atrial fibrillation in 2 patients (0.022%), complete atrioventricular block in 2 patients (0.022%), ventricular fibrillation in 1 patient (0.011%), nodal rhythm in 6 patients (0.066%), perforation of the right ventricular wall in 1 patient (0.011%), hematoma of the right ventricular wall in 2 patients (0.022%), anonymous vein lesion in 2 patients (0.022%), and pulmonary artery rupture in 2 patients (0.022%).</AbstractText>Pulmonary artery catheterization performed by experienced team appears to be a safe procedure in cardiac surgery patients.</AbstractText>

Cariporide enables hemodynamically more effective chest compression by leftward shift of its flow-depth relationship.

When given during closed-chest resuscitation, cariporide (4-isopropyl-methylsulfonylbenzoyl-guanidine methanesulfonate; a selective inhibitor of the Na(+)/H(+) exchanger isoform-1) enables generation of viable perfusion pressures with less depth of compression. We hypothesized that this effect results from greater blood flows generated for a given depth of compression. Two series of 14 rats each underwent 10 min of untreated ventricular fibrillation followed by 8 min of chest compression before defibrillation was attempted. Compression depth was adjusted to maintain an aortic diastolic pressure (ADP) between 26 and 28 mmHg in the first series and between 36 and 38 mmHg in the second series. Within each series, rats were randomized to receive cariporide (3 mg/kg) or NaCl (0.9%; control) before chest compression was started. Blood flow was measured using 15-mum fluorescent microspheres. Less depth of compression was required to maintain the target ADP when cariporide was present in both series 1 (13.6 +/- 1.2 vs. 16.6 +/- 1.2 mm; P &lt; 0.001) and series 2 (15.3 +/- 1.0 vs. 18.9 +/- 1.5 mm; P &lt; 0.001). Despite less compression depth, the cardiac index in cariporide-treated rats was comparable to control rats in series 1 (11.1 +/- 0.7 vs. 11.3 +/- 1.4 ml.min(-1).kg(-1); P = not significant) but higher in series 2 (15.5 +/- 2.3 vs. 9.9 +/- 1.4 ml.min(-1).kg(-1); P &lt; 0.05). Increases in compression depth (from series 1 to series 2) increased myocardial, cerebral, and adrenal blood flow in cariporide-treated rats. We conclude that cariporide enhances the efficacy of closed-chest resuscitation by leftward shift of the flow-depth relationship.

Antiarrhythmic effect of carvedilol after acute myocardial infarction: results of the Carvedilol Post-Infarct Survival Control in Left Ventricular Dysfunction (CAPRICORN) trial.

Whether beta-blockers reduce atrial arrhythmias and, when added to an angiotensin-converting enzyme (ACE) inhibitor, ventricular arrhythmia is unknown.</AbstractText>Ventricular and atrial arrhythmias are common after acute myocardial infarction (AMI) and are associated with a poor prognosis. Angiotensin-converting enzyme inhibitors reduce the incidence of both types of arrhythmia.</AbstractText>The antiarrhythmic effect of carvedilol was examined in a placebo-controlled multicenter trial, the Carvedilol Post-Infarct Survival Control in Left Ventricular Dysfunction (CAPRICORN) study, which enrolled 1,959 patients with reduced left ventricular systolic function after AMI, 98% of whom were treated with an ACE inhibitor.</AbstractText>The incidence of atrial fibrillation/flutter was 53 to 984 (5.4%) in the placebo group and 22 to 975 (2.3%) in the carvedilol group, giving a carvedilol/placebo hazard ratio (HR) of 0.41 (95% confidence interval [CI] 0.25 to 0.68; p = 0.0003). The corresponding rates of ventricular tachycardia/flutter/fibrillation were 38 to 984 (3.9%) and 9 to 975 (0.9%) (HR 0.24, 95% CI 0.11 to 0.49; p &lt; 0.0001).</AbstractText>Carvedilol has a powerful antiarrhythmic effect after AMI, even in patients already treated with an ACE inhibitor. Carvedilol suppresses atrial as well as ventricular arrhythmias in these patients.</AbstractText>

Programmed ventricular stimulation in patients with idiopathic dilated cardiomyopathy and syncope receiving implantable cardioverter-defibrillators: a case series and a systematic review of the literature.

The role of programmed ventricular stimulation (PVS) in patients with idiopathic dilated cardiomyopathy (DCM) and syncope receiving implantable cardioverter-defibrillators (ICD) remains controversial.</AbstractText>Between 1994 and July 2002, 20 patients with DCM and syncope underwent PVS and ICD implantation at the Onassis Cardiac Surgery Center or the Alexandra General Hospital. At PVS 10 patients had inducible sustained monomorphic ventricular tachycardia (SMVT), 3 patients had inducible sustained polymorphic ventricular tachycardia or ventricular fibrillation, and 7 patients had no inducible arrhythmia. The latter 7 patients received an ICD because of clinical occurrence of ventricular tachycardia (n=5) or fibrillation (n=2). Mean age was 55+/-14 years; 80% were men. During a mean follow-up of 2.8+/-2.3 years, 12 of the 20 patients received an appropriate shock. The incidence of appropriate shocks at 1 and 3 years was 69% and 84% in the inducible SMVT group, and 56% and 67% in the group without inducible SMVT (p=0.93, log rank test). Overall survival was similar in both groups (p=0.53). In a systematic review of the published literature 18 of 75 (24%) patients with DCM, syncope and a negative PVS had an appropriate ICD shock after a mean follow-up of 27 months.</AbstractText>PVS has a limited role in risk stratification of patients with DCM and syncope.</AbstractText>

Antithrombotic strategies in patients with an indication for long-term anticoagulation undergoing coronary artery stenting: safety and efficacy data from a single center.

Dual antiplatelet therapy is the antithrombotic treatment generally recommended after percutaneous coronary intervention with stent implantation (PCI-S). However, the optimal antithrombotic treatment after PCI-S in case of a concomitant indication for anticoagulation (AC) is unknown. The aim of our study was to determine the strategies adopted at our Institution (where the management of these patients is at the physician's discretion), and to evaluate their relative efficacy and safety.</AbstractText>A retrospective analysis of all PCI-S performed between January 2002-April 2004, was carried out. All patients on AC at the time of PCI-S were identified and the hemorrhagic and thromboembolic complications recorded.</AbstractText>Twenty-seven patients (21 males, 6 females, mean age 66.9 +/- 10.6 years) on AC because of atrial fibrillation, post-myocardial infarction cardiomyopathy, left ventricular or arterial thrombus, previous cerebrovascular event, and mechanical aortic or mitral valve, were identified. The adopted antithrombotic treatment included: dual antiplatelet therapy in 6 patients (22%), a combination of a single antiplatelet with either aspirin or a thienopyridine and oral AC in 5 (19%), and triple therapy with dual antiplatelet and either oral AC or low-molecular-weight heparin administration in 16 (59%). The overall complication rate at 32.3 +/- 5.4 days was 18%, accounted for by two in-hospital major hemorrhages requiring blood transfusion (7%), two minor hemorrhages treated conservatively (7%), and one subacute stent thrombosis requiring emergency percutaneous reintervention (4%).</AbstractText>At our Institution, variable antithrombotic strategies are adopted after PCI-S in patients with an indication for AC. Since the overall complication rate was relevant, further properly sized and designed studies are warranted in order to identify the optimal antithrombotic treatment in this patient subset.</AbstractText>

Overdrive pacing of early ischemic ventricular tachycardia: evidence for both reentry and triggered activity.

Entrainment can be a useful method to identify reentry as a mechanism of ventricular tachycardia (VT). In this study, we evaluated the effect of gradually decreasing cycle lengths of overdrive pacing for stable VT induced in a canine model 1-3 h after coronary occlusion. Intact dogs underwent anterior descending coronary artery occlusion after instrumentation of the risk zone with 21 multipolar plunge needles, each recording 6 bipolar electrograms. Overdrive pacing was attempted if the animals had sustained hemodynamically stable VT, looking for evidence of entrainment. Subsequent three-dimensional mapping determined the mechanism of VT. Fifteen of the 21 dogs studied demonstrated entrainment with overdrive pacing by progressive QRS fusion alone (1), the first nonpaced QRS entrained to the paced cycle length only (7), or both (7). Five of these 15 dogs also had postpacing acceleration of the VT at a subsequent faster pacing cycle length. The mechanism of acceleration in four was a change to a VT with a focal origin. The prepacing mechanism in all 15 dogs was subsequently mapped to reentry. Regarding the six VTs, which demonstrated no evidence for entrainment, the site of earliest activity was mapped to a focal origin in all. These data showing entrainment of inducible reentrant VTs and lack of such for focal VTs support that the focal VTs seen in this study are unlikely the result of microreentry but possibly a mechanism as triggered activity.

Prediction of successful cardioversion and maintenance of sinus rhythm in patients with lone atrial fibrillation.

We aimed to prospectively investigate the predictive value of echocardiographic parameters for the prediction of successful cardioversion and long-term sinus rhythm (SR) maintenance in patients who have experienced a lone episode of atrial fibrillation (AF).</AbstractText>Clinical and echocardiographic data, including mean left atrial appendage (LAA) peak flow velocity and mitral annulus motion, were analyzed in 78 consecutive patients (mean [+/- SD] age, 59.3 +/- 9.3 years) with AF lasting &gt; 48 h and &lt; 6 months. Sixty-one patients (78%) underwent successful external electrical cardioversion, while the remaining remained in AF. At the 1-year follow-up, of the 61 patients who had successfully been converted to SR, 24 (39.3%) remained in SR. For predicting the success of the cardioversion, we used a model consisting of two variables. LAA flow velocity (&gt; 20 cm/s) and left ventricular (LV) fractional shortening (&gt; 30%) appear to be quite strong, yielding 83.3% correct results. For predicting the maintenance of SR, we used a model consisting of two variables. The absence of the early systolic abnormal mitral annulus motion and LAA flow velocity (&gt; 20 cm/s) appears to be quite strong, yielding 84.6% correct results. LAA flow velocity only marginally enters the model, and, if removed, little predictive value is lost (dropping to 83.3%). Removing the early systolic abnormal mitral annulus motion variable, the prediction value drops significantly to 70.5%.</AbstractText>LAA flow velocity combined with LV fractional shortening can predict the success of the conversion of AF to SR. Additionally, LAA flow velocity, combined with the analysis of mitral annulus motion before cardioversion, can predict the long-term maintenance of SR.</AbstractText>

Implantable cardioverter-defibrillators, induced anxiety, and quality of life.

Since its approval in 1985, the implantable cardioverter-defibrillator (ICD) has supplanted antiarrhythmic drugs as the standard of care for patients with potentially lethal ventricular arrhythmias. The increased popularity of ICDs stems primarily from their safety and tolerability compared with commonly used medications notorious for adverse drug reactions. As ICD indications have broadened, the number of implantations has increased substantially, and more attention has been directed to sequelae of implantation, particularly after ICD firing. Although scant, studies of quality of life and psychiatric symptoms in patients with ICDs consistently report assorted psychiatric disturbances affecting up to 87% of recipients. Depression and anxiety predominate: up to 38% of patients experience symptoms that meet diagnostic criteria for an anxiety disorder. Psychological theories such as the classic conditioning model, learned helplessness model, and cognitive appraisal model have been invoked to conceptualize these new-onset ICD-induced anxiety disorders. Small trials of psychosocial interventions, including support groups and cognitive behavioral therapy, have had mixed results. Little is known about preexisting anxiety disorders in ICD recipients, particularly which premorbid features predict a worse prognosis, other than suggestions that younger patients and those receiving multiple shocks are at greater risk. Prospective studies of the psychopathology of patients with ICDs, both before and after implantation, are warranted.

[Indications for automatic implantable defibrillators in patients with the Brugada syndrome].

Brugada syndrome is a primary electrical cardiac disease characterized by an ST segment elevation in V1-V2 leads on surface ECG and an increased risk of polymorphic ventricular tachyarrhythmia (ventricular tachycardia and/or ventricular fibrillation). The objective of the treatment is to prevent sudden death and it therefore includes in some cases the implantation of an automatic implantable cardiac defibrillator (AICD). In secondary prevention (i.e. after a first episode of resuscitated ventricular fibrillation), the implantation of AICD is mandatory (indication of class 1 level A). In primary prevention (i.e. in patients without documented ventricular fibrillation), the guidelines are not definitively established. We may consider two different clinical situations. First, the patient complains from syncope and this justifies the implantation of an AICD. Second, the patient is asymptomatic and the physician has to discuss the implantation of an AICD. Two parameters should be analysed: the pattern of ECG and the result of right programmed ventricular stimulation. An evident ST segment elevation (&gt;2 mm) is associated with a high risk of sudden death. Likewise, the inducibility of a ventricular tachycardia or fibrillation is considered at the present time as a factor linked to sudden death and justifies the implantation of an AICD. On the other hand, a normal resting ECG only associated with a provoked ST segment elevation by class I antiarrhythmic drug (flecainide) defines a group of patients with a low risk of sudden death, and these patients do not require the implantation of an AICD.

[Cardiac resynchronisation therapy: what kind of equipment to use?].

Cardiac resynchronization therapy is indicated in advanced heart failure refractory to optimal drug treatment patients with left ventricular systolic dysfunction and QRS &gt;120 milliseconds. The choice of the device has to consider several parameters: Do we have to implant a CRT pacemaker or a intracardiac cardioverter defibrillator (ICD)? The prevalence of sudden cardiac death is high in heart failure patients. In patients with an ischemic cardiomyopathy, primary prevention of sudden cardiac death trials suggests to implant a biventricular ICD. In patients with a non ischemic cardiomyopathy, the question is more controversial althought the resullts of the SCD-HeFT and COMPANION trials yielded interesting results for iCD implantation. However, the final decision has to consider the patient's baseline characteristics such as age, presence of comorbidities and cost of the device. Today, devices with totally independent ports of the right and left ventricles have technical advantages and thus are more relevant. Cardiac resynchronization therapy is a heart failure treatment and the new devices provide new tools to assess heart failure parameters such as patient's activity, respiratory parameters or heart rate variability. Left ventricular pacing alone is currently under evaluation such as atrial fibrillation prevention algorithms, atrial fibrillation being frequent in herta failure patients with hemodynamic deleterious consequences.

[Successful defibrillation by disconnection of superior vena cava electrode for high defibrillation threshold: a case report].

A 72-year-old man with dilated cardiomyopathy and sustained ventricular tachycardia was treated with amiodarone. He visited another hospital because of loss of consciousness. Electrocardiography showed 2: 1 atrioventricular block. Ambulatory electrocardiography showed total heart beats were 59,700 per day. He was referred to our hospital to evaluate his heart. Several types of ventricular tachycardia and ventricular fibrillation were induced by program stimulation during the electrophysiological study. Therefore, an implantable cardioverter-defibrillator was introduced. During defibrillation threshold tests, ventricular fibrillation could not be terminated by the maximal output of 31J. Despite changing the polarity and lead position, stable defibrillation could not be obtained. Finally, successful defibrillation could only be achieved by disconnection of the superior vena cava electrode.

[Long-term preventive effect and safety of amiodarone in patients with paroxysmal atrial fibrillation refractory to class I antiarrhythmic agents: analysis based on patient profiles].

The factors controlling the preventive effect of long-term amiodarone therapy were evaluated in patients with paroxysmal atrial fibrillation. The 55 patients (37 men and 18 women, mean age 68 +/- 9 years) with paroxysmal atrial fibrillation refractory to more than two types of Class I antiarrhythmic agents received amiodarone (100-200mg/day) after electrical or pharmacological cardioversion. All patients were observed for 12 months or more (mean follow-up period 48.6 +/- 29.1 months).</AbstractText>Actuarial recurrence-free rate at 12 months in patients with ejection fraction &lt; 55% (76.5%, n = 17) was significantly higher than that in patients with ejection fraction &gt; or = 55% (44.7%, n = 38) (p = 0.0411), and tended to be higher in patients with underlying heart disease (65.5%, n = 29) than in patients without underlying heart disease (42.3%, n = 26) (p = 0.0980). Age, sex, diabetes mellitus, alcohol intake, hypertension, hyperlipidemia, and administration of angiotensin converting enzyme inhibitor were not related to the effect of amiodarone. Relative risk reduction of recurrence after amiodarone therapy was 4.01 (95% confidence interval 3.57-4.45) in patients with ejection fraction &lt; 55%, and 2.59 (95% confidence interval 2.07-3.11) in patients with underlying heart disease. None of the above-mentioned factors was related to the development of adverse effects. The incidence of adverse effects requiring discontinuation in all patients was 7.3%.</AbstractText>Amiodarone was more effective for preventing recurrence in patients with poorer left ventricular function and underlying heart disease.</AbstractText>

[Stroke and other thromboembolic complications of atrial fibrillation. Part VI. Choice of optimal approach and drugs for prevention of stroke].

In part VI of a series of papers on epidemiology and drug prevention of stroke and other thromboembolic complications of atrial fibrillation the authors analyze data of randomized trials comparing various approaches to the treatment of atrial fibrillation: cardioversion with subsequent use of antiarrhythmic drugs for maintenance of sinus rhythm and control of rate of ventricular rhythm with obligatory concomitant use of anticoagulants. Approach aimed at sinus rhythm maintenance by means of repetitive cardioversions and long term antiarrhythmic therapy has not been associated with lowering of mortality, rates of stroke or other thromboembolic complications. The use of antithrombotic drugs represent a sole reliable method of stroke prevention in patients with persistent and chronic AF. The paper contains consideration of indications for prescription of warfarin and aspirin to these patients.

[The role of atrial pressure in spontaneous initiation of atrial fibrillation in the dog.].

Atrial fibrillation (AF) frequently occurred under conditions associated with atrial dilatation (stretch) or vagal hyperactivity. To study possible role of atrial stretch in spontaneous initiation of vagal AF we compared changes of right atrial pressure (RAP) and activation patterns during AF beginning. In anesthetized open-chest dogs (n=45) AF was induced by stimulation of vagal nerves (VS) (30-60 Hz, 5-10 s train). VS resulted in sinus node arrest (4.7+/-0.7 sec) with subsequent AF initiation in 153 of 229 cases. In 41% of cases of AF initiation the first atrial wave (A(1)) was closely related to ventricular activation (V) with V-A(1) interval of 94+/-5 ms (&lt;&lt;ventricle-dependent&gt;&gt; AF). This ventricular excitation induced acute short increase of RAP from 6.6.+/-0.6 to 12.9+/-1.1 mmHg (p&lt;0.00l). Whereas other cases of AF initiation (59%) had no relation to ventricular activation (A(1)-V interval of 1382+/-173 ms) (&lt;&lt;ventricle-independent&gt;&gt; AF). Atrial activation mapping (224 unipolar electrodes) showed that interval A(1)-A(2) of &lt;&lt;ventricle-dependent&gt;&gt; AF was significantly shorter than of &lt;&lt;ventricle-independent&gt;&gt;. These data indicate that atrial stretch induced by elevation of RAP may facilitate the induction of AF but do not play a significant role in the mechanism of spontaneous AF initiation in this animal model.

Preventing alternans-induced spiral wave breakup in cardiac tissue: an ion-channel-based approach.

The detailed processes involved in spiral wave breakup, believed to be one major mechanism by which tachycardia evolves into fibrillation, are still poorly understood. This has rendered difficult the proper design of an efficient and practical control stimulus protocol to eliminate such events. In order to gain new insights into the underlying electrophysiological and dynamical mechanisms of breakup, we applied linear perturbation theory to a steadily rotating spiral wave in two spatial dimensions. The tissue was composed of cells modeled using the Fenton-Karma equations whose parameters were chosen to emphasize alternans as a primary mechanism for breakup. Along with one meandering mode, not just one but several unstable alternans modes were found with differing growth rates, frequencies, and spatial structures. As the conductance of the fast inward current was increased, the instability of the modes increased, consistent with increased meandering and propensity for spiral breakup in simulations. We also explored a promising new approach, based on the theory, for the design of an energy efficient electrical stimulus protocol to control spiral wave breakup. The novelty lies in addressing the problem directly at the ion channel level and taking advantage of the inherent two dimensional nature of the rotating wave. With the help of the eigenmode method, we were able to calculate the exact timing and amplitude of the stimulus, and locate it optimally to maximize efficiency. The analysis led to a special-case example that demonstrated that a single, properly timed stimulus can have a global effect, suppressing all growing alternans modes over the entire tissue, thus inhibiting spiral wave breakup.

Effect of statin therapy on risk of ventricular arrhythmia among patients with coronary artery disease and an implantable cardioverter-defibrillator.

Hydroxymethylglutaryl coenzyme-A reductase inhibitors, or statins, have been shown to decrease mortality rates in patients who have coronary artery disease. It has been postulated that part of the mortality benefit conferred by statins is due to a decrease in ventricular arrhythmias. We assessed the effect of statin therapy on recurrent ventricular arrhythmias in 281 patients who developed coronary artery disease after implantable cardioverter-defibrillator placement. Statin therapy was associated with a significant decrease in the risk of ventricular arrhythmia that would require implantable cardioverter-defibrillator therapy.

Cardiovascular abnormalities in hyperthyroidism: a prospective Doppler echocardiographic study.

We investigated the prevalence and clinical importance of cardiovascular abnormalities in patients with hyperthyroidism.</AbstractText>All consecutive patients diagnosed with hyperthyroidism during a period of 24 months were included in the study. Medical history, complete physical examination results, electrocardiographic findings, laboratory determinations, and Doppler echocardiographic findings were obtained for all patients within 24 hours of diagnosis, and after euthyroidism had been achieved. Age- and sex-matched controls also were studied.</AbstractText>Thirty-nine patients (mean [+/-SD] age, 52 +/- 20 years; range, 25 to 86 years; 72% women), and 39 age- and sex-matched controls, were included. Atrial fibrillation was present in 7 patients (18%). Moderate or severe mitral or tricuspid regurgitation, or both, were present in 9 patients (23%) and in only 1 control (3%; P= 0.01). Mean pulmonary arterial systolic pressure was 38 +/- 12 mm Hg (range, 17 to 64 mm Hg) in patients and 27 +/- 4 mm Hg (range, 19 to 37 mm Hg) in controls (P= 0.001). Sixteen patients (41%) and 1 control (3%) had pulmonary arterial systolic pressure &gt;or=35 mm Hg. Left ventricular systolic dysfunction was detected in 1 patient. After correction of hyperthyroidism, a significant decrease in pulmonary arterial systolic pressure was observed, and the levels became similar to those of controls.</AbstractText>In patients with hyperthyroidism, there is a high prevalence of pulmonary hypertension and atrioventricular valve regurgitation. These abnormalities usually correct after treatment for hyperthyroidism.</AbstractText>

Endoventriculoplasty using autologous endocardium for anterior left ventricular aneurysms.

There is currently consensus that endoventriculoplasty is the treatment of choice for an anterior left ventricular aneurysm. We describe here a new technique of endoventriculoplasty using autologous endocardium for left ventricular anterior aneurysm.</AbstractText>From 1990 until 2003, 49 patients underwent endoventriculoplasty using autologous pericardium at the Thoraxcenter of the University Hospital of Groningen in the Netherlands (28 patients) and at the Department of Cardio Thoracic Surgery of the University Hospital of Pisa in Italy (21 patients). Mean logistic EuroSCORE and mean ejection fraction were 15.7 +/- 6.7 and 31 +/- 9 %, respectively.</AbstractText>Overall 30-day mortality was 4.1 %. Causes of in-hospital mortality were low output syndrome (1 patient) and ventricular fibrillation (1 patient). Postoperative complications were myocardial infarct (4.1 %), low output syndrome (6.1 %), renal failure (4.1 %), neurological events (2.0 %), atrial fibrillation (14.3 %), ventricular fibrillation or tachycardia (6.1 %), ARDS (4.1 %), re-operation for bleeding (4.1 %), and major wound infection (2.0 %).</AbstractText>Our analysis shows that endoventriculoplasty with autologous endocardium is a safe procedure and improves the outcome in high-risk patients with ventricular aneurysm.</AbstractText>

Surgical treatment of atrial fibrillation; a systematic review.

In this review the efficacies of the alternative sources of energy (radiofrequency-microwave and cryo ablation; group I) and the classical 'cut and sew' Cox-Maze III (group II), which claims a 97-99% sinus rhythm (SR) success rate, were evaluated in the surgical treatment of atrial fibrillation (AF). A computerized search in the PubMed and Medline database was conducted. Only original, English written, clinical manuscripts on the surgical treatment of atrial fibrillation using an alternative source of energy or the classical 'cut and sew' Cox-Maze III technique, citing the clinical outcome, including the postoperative sinus rhythm, were included. The data included in this review were the number and percentage of treated patients, gender distribution, the type of arrhythmia and surgery, postoperative morbidity, pacemaker implantation rate, 30-day mortality, survival- and sinus rhythm conversion rates. Mean values for age, left atrial diameter, preoperative duration of AF and left ventricular ejection fraction were also recorded. Forty-eight studies were included comprising 3832 patients; 2279 in group I and 1553 in group II. The mean duration of AF, left atrial diameter and LVEF were 5.4 vs. 5.5 years (p=0.90), 55.5 vs. 57.8 mm (p=0.23) and 57 vs. 58% (p=0.63). The postoperative SR rates for group I and II were 78.3 vs. 84.9% (p=0.03). However, the "cut and sew" Cox-Maze III was conducted in younger patients (55.0 vs. 61.2 years; p=0.005), more often to treat paroxysmal (22.9 vs. 8.0%; p=0.05) and lone AF (19.3 vs. 1.6%). Alternative sources of energy were predominantly used to treat permanent AF (92.0%), almost always as a concomitant surgical procedure (98.4%) and increasingly in combination with non-mitral valve surgery (18.5%). After correction for these variations, the postoperative SR conversion rates for group I and II did not differ significantly anymore (p=0.260).</AbstractText>We could not identify any significant difference in the postoperative SR conversion rates between the classical 'cut and sew' and the alternative sources of energy, which were used to treat atrial fibrillation.</AbstractText>

Defibrillation and biphasic shocks: Implications for perianesthesia nursing.

Cardiac arrests, the majority of which are due to ventricular fibrillation (VF), are a significant threat to survival. The definitive therapy for cardiac arrests due to VF is rapid, early defibrillation. There have been several advances made to modern defibrillators to electively or emergently terminate lethal and nonlethal arrhythmias through external defibrillation. The most recent improvement is in the efficacy of the delivered shock. Biphasic shock waveforms have been shown to be superior to monophasic shocks and are recognized in the current Advanced Cardiac Life Support guidelines by the American Heart Association. Because hospitals are increasingly replacing older models of monophasic capability defibrillators with the newer biphasic capability models, it will be essential for perianesthesia nurses to understand the principles of biphasic technology.

Electrophysiological evaluation of asymptomatic ventricular pre-excitation in children and adolescents.

Diagnostic assessment and treatment have been described in detail in symptomatic WPW syndrome, but little information exists about significance and prognosis of an incidentally found ventricular pre-excitation (VPE) in asymptomatic children. The aim of the study was to evaluate, retrospectively, the role of electrophysiological study (EPS) in the assessment of the arrhythmic risk in asymptomatic patients with VPE.</AbstractText>Sixty-two asymptomatic children and adolescents (38 M/24 F, aged 9.8+/-5.1 years) referred to our Division between 1996 and 2002 for an incidentally found VPE underwent an EPS for arrhythmic risk stratification. The following parameters were examined: anterograde effective refractory period of the accessory pathway (AP), the 1-to-1 conduction over the AP, the inducibility of atrio-ventricular re-entrant tachycardia (AVRT) and the inducibility of atrial fibrillation (AF) with measurement of minimal RR between two consecutive preexcitated QRS complexes, the average RR interval of all cycles, and the percentage of preexcitated QRS complexes.</AbstractText>During the EPS, 36 patients (58.1%) experienced sustained SVT. The tachycardia was initiated in the basal state in 22 patients and after isoproterenol in the other 14. Orthodromic AVRT (cycle length 305.9+/-48.5 ms) was recorded in 29 patients. In three patients, both orthodromic and antidromic AVRT were recorded, with different cycle length (CL). Antidromic AVRT alone (CL 239.5+/-13.7 ms) was recorded in four patients. AF was recorded in nine patients: in six patients, it was recorded after the induction of orthodromic or antidromic AVRT, in the other three cases AF was the first and only arrhythmic event. The minimal RR between two consecutive pre-excitated QRS ranged between 250-230 ms (mean 237.5+/-9.6 ms). In the 26 patients who presented no induced sustained tachycardia in the EPS, the 1:1 conduction over the AP ranged between 210 and 600 ms (mean 279.6+/-75.2 ms).</AbstractText>Electrophysiological evaluation remains the gold standard for assessing risk of life-threatening arrhythmias in patients with VPE. However, a high proportion of healthy children and adolescents with VPE can experience sustained AVRT and/or AF during EPS. These results raise questions about the necessity of an aggressive treatment approach to prevent those "rare" cases of sudden death.</AbstractText>

A new dual-chamber pacing mode to minimize ventricular pacing.

Despite the low long-term incidence of high-degree atrioventricular (AV) block and the known negative effects of ventricular pacing, programming of the AAI mode in patients with sinus node dysfunction (SND) remains exceptional. A new pacing mode was, therefore, designed to combine the advantages of AAI with the safety of DDD pacing. AAIsafeR behaves like the AAI mode in absence of AV block. First- and second-degree AV blocks are tolerated up to a predetermined, programmable limit, and conversion to DDD takes place in case of high-degree AV block. From DDD, the device may switch back to AAI, provided AV conduction has returned. The safety of AAIsafeR was examined in 43 recipients (70 +/- 12-year old, 24 men) of dual chamber pacemakers implanted for SND or paroxysmal AV block. All patients underwent 24-hour ambulatory electrocardiographic recordings before hospital discharge and at 1 month of follow-up with the AAIsafeR mode activated. No AAIsafeR-related adverse event was observed. At 1 month, the device was functioning in AAIsafeR in 28 patients (65%), and the mean rate of ventricular pacing was 0.2%+/- 0.4%. Appropriate switches to DDD occurred in 15 patients (35%) for frequent, unexpected AV block. AAIsafeR mode was safe and preserved ventricular function during paroxysmal AV block, while maintaining a very low rate of ventricular pacing. The performance of this new pacing mode in the prevention of atrial fibrillation will be examined in a large, controlled study.

Characteristics of bifocal pacing: right ventricular apex versus outflow tract. An interim analysis.

Bifocal RIGHT ventricular stimulation (BRIGHT) is an ongoing, randomized, single-blind, crossover study of atrial synchronized bi-right ventricular (RV) pacing in patients in New York Heart Association heart failure functional class III, a left ventricular ejection fraction &lt;35%, left bundle branch block and QRS complexes &gt;/=120 ms. This analysis compared the electrical and handling characteristics, and the complications of pacing at the RV apex (Ap) with passive, versus RV outflow tract (OT) with active fixation leads. A mean of 1.6 +/- 0.9 and 2.2 +/- 2.0 attempts were needed to position the Ap and OT leads, respectively (ns). R-wave amplitudes at Ap versus OT were 23 +/- 13 mV versus 14 +/- 8 mV (n = 36, P &lt; 0.001). R-wave amplitudes at the Ap remained stable between implant and M7. R-wave amplitudes at the OT could not be measured after implantation. In two patients, atrioventricular block occurred during active fixation at the OT. Conduction recovered spontaneously within 4 months. Ventricular fibrillation was induced in one patient during manipulation of an Ap lead in the RV. Marked differences were found between leads positioned in the OT versus Ap, partly related to the difference in lead design. Mean R-wave amplitude was higher at the Ap that at the OT. Ease and success rate of lead implant was similar in both positions.

Cardiac safety of neuromuscular incapacitating defensive devices.

Neuromuscular incapacitation (NMI) devices discharge a pulsed dose of electrical energy to cause muscle contraction and pain. Field data suggest electrical NMI devices present an extremely low risk of injury. One risk of delivering electricity to a human is the induction of ventricular fibrillation (VF). We hypothesized that inducing VF would require a significantly greater NMI discharge than a discharge output by fielded devices. The cardiac safety of NMI discharges was studied in nine pigs weighing 60 +/- 28 kg. The minimum fibrillating level was defined as the lowest discharge that induced VF at least once, the maximum safe level was defined as the highest discharge which could be applied five times without VF induction, and the VF threshold was defined as their average. A safety index was defined as the ratio of the VF threshold to the standard discharge level output by fielded NMI devices. A VF induction protocol was applied to each pig to estimate the VF threshold and safety index. The safety index for stored charge ranged from 15X to 42X as weight increased from 30 to 117 kg (P &lt; 0.001). Discharge levels above standard discharge and weight were independently significant for predicting VF inducibility. The safety index for an NMI discharge was significantly and positively associated with weight. Discharge levels for standard electrical NMI devices have an extremely low probability of inducing VF.

Value of pre-hospital discharge defibrillation testing in recipients of implanted cardioverter defibrillators.

Opinions vary regarding the need to perform defibrillation testing prior to hospital discharge in recipients of state-of-the-art cardioverter defibrillators (ICDs). Our protocol is to perform predischarge ICD testing 1 day after implant. This report includes 682 consecutive implants. Adverse observations at testing were grouped into (1) risk of defibrillation failure, (2) surgical complications, (3) sensing/pacing issues or narrow defibrillation margin warranting closer follow-up, or (4) findings correctable by device reprogramming. Among the 682 patients, 63% had single-chamber and 37% dual-chamber or biventricular ICDs. In 48 patients (7%) there were 69 concerns and/or interventions, with overlaps among the four categories, including one failure to defibrillate (0.15%), and six other patients at risk. Surgical complications included 11 hematomas (1.6%), and six lead dysfunctions. Closer follow-up was indicated in 19 patients (2.7%), for high pacing thresholds in seven, sensing issues in seven, and &lt;10 J defibrillation margin in five. Device reprogramming was needed in 31 patients (4.5%), for tachycardia detection and therapy settings in 12, and for pacing/sensing functions in 22 patients. In eight patients ventricular fibrillation could not be induced. There was no morbidity or mortality due to testing. The state-of-the-art ICDs delivering biphasic shocks are remarkably reliable. The routine pre-hospital discharge defibrillation testing of such ICDs may be optional and left to the physicians' discretion.

Changes in autonomic nervous activity after catheter ablation of atrial tachycardia arising from the atrioventricular annulus.

Radiofrequency (RF) catheter ablation of supraventricular tachycardias causes local parasympathetic denervation. This study used heart rate variability (HRV) to evaluate the effects of ablation of atrial tachycardia (AT) arising from the atrioventricular annulus (AVAT) on autonomic function. Ten patients with AVAT were referred for ablation (group AT) and compared with 8 patients with paroxysmal atrial fibrillation who underwent PV isolation (group Paf), and 13 patients with idiopathic ventricular tachycardia successfully treated by ablation (group VT). Time and frequency domain analysis of HRV on 24-hour ambulatory ECG recordings was performed before and after ablation. Root mean square of differences of consecutive N-N intervals (rMSSD), percentage of difference between consecutive N-N intervals &gt;50 ms (pNN50), and high frequency (HF) component were measured to examine the effects on parasympathetic nerve activity. In group AT, rMSSD, pNN50, and HF decreased significantly after ablation, while they remained unchanged in group Paf and group VT. These observations suggest that parasympathetic denervation after ablation was limited to group AT, and depended on the site of energy delivery along the tricuspid or mitral valve as opposed to atrial or ventricular muscle.