bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of acute alcohol infusion on duration and dispersion of QT interval in male patients with coronary artery disease and in healthy controls
Authors: Rossinen Juhani , Sinisalo Juha , Nieminen Markku S. , Vittasalo Matti , Partanen Juhani
Published: February 2009

Background and hypothesis: Alcohol consumption may have advantageous epidemiologic effects but ethanol also increases the risk of sudden coronary death. Prolongation of QT interval has been reported in chronic alcoholics. Long QT period predisposes to serious arrhythmias, and therefore we studied whether acute alcohol intoxication prolongs repolarization in patients with stable coronary artery disease (CAD).

Methods: The effects of acute ethanol steady‐state intravenous infusion (0.72 g/kg body weight within 60 min) on QT interval and QT dispersion, assessed by 12‐lead electrocardiograms (ECG), were studied in 22 men with stable CAD and in 10 controls. Heart rate variability was measured by Holter recordings.

Results: Mean blood alcohol rose to 26.1 ± 4.3 mmol/l (1.2 ± 0.2%), and was maintained for 2 h. Heart rate was 56 ± 7 beats/min before and 54 ± 8 beats/min during ethanol infusion (NS). The heart rate‐adjusted QT interval increased on the average 13–23 ms over the 12‐lead ECG (p < 0.005). The QT dispersion remained unaltered. The was no difference in the repolarization response in the patients with CAD compared with the controls. The high‐ and low‐frequency components of heart rate variability remained unaltered.

Conclusions: in middle aged men, regardless of the presence of CAD, moderate amounts of alcohol cause prolongation of ventricular repolarization. Changes in the activity of the autonomic nervous system do not seem to explain the observed phenomenon.
Use of QT dispersion measured on treadmill exercise electrocardiograms for detecting restenosis after percutaneous transluminal coronary angioplasty
Authors: Koide Yasushi , Yotsukura Masayuki , Tajino Kazuhiro , Yoshino Hideaki , Ishikawa Kyozo
Published: February 2009

Background: Treadmill exercise electrocardiography (ECG) has been used to detect restenosis in patients following percutaneous transluminal coronary angioplasty (PTCA). However, the level of sensitivity achieved using conventional criteria of ST‐segment depression is too low to be clinically useful in this population.

Hypothesis: QT dispersion is a sensitive method for detecting myocardial ischemia and may improve the accuracy of treadmill exercise ECG testing for detecting restenosis after PTCA.

Methods: We evaluated 104 patients who underwent PTCA for the treatment of single‐vessel coronary artery disease and who had no history of myocardial infarction. Treadmill exercise ECG and coronary angiograms were performed 3 months after PTCA to determine the accuracy of diagnosing restenosis based on standard ST‐segment depression and QT dispersion criteria.

Results: Restenosis was observed in 37 of the 104 patients (36%) 3 months after PTCA. QT dispersion immediately after exercise was significantly greater in patients with than in those without restenosis, as was the difference in QT dispersion before and immediately after exercise. The sensitivity, specificity, and accuracy of ST‐segment depression criteria were 59, 64, and 63%, respectively. Measurements of QT dispersion immediately after exercise (≥50 ms: positive, <50 ms: negative) improved the sensitivity, specificity, and accuracy of treadmill ECG for predicting restenosis to 81, 87, and 85%, respectively.

Conclusions: This novel diagnostic method using QT dispersion‐based criteria significantly improves the clinical usefulness of treadmill exercise ECG for detecting the presence of restenosis after PTCA.
Relation of ventricular repolarization to cardiac cycle length in normal subjects, hypertrophic cardiomyopathy, and patients with myocardial infarction
Authors: Savelieva Irina , Yap Yee Guan , Yi Gang , Guo Xiao Hua , Hnatkova Katerina , John Camm A. , Malik Marek
Published: February 2009

Background: Prolonged QT interval and QT dispersion have been reported to reflect an increased inhomogeneity of ventricular repolarization, which is believed to be responsible for the development of arrhythmic events in patients with long QT syndrome, coronary heart disease, and myocardial infarction, congestive heart failure, and hypertrophic cardiomyopathy (HC).

Hypothesis: This study was undertaken to determine whether an abnormal QT/RR dynamicity may reflect autonomic imbalance and may contribute to arrhythmogenesis in patients with heart disease.

Methods: The relation between QT, QTpeak (QTp), Tpeak‐Tend (TpTc) intervals and cardiac cycle length was assessed in 70 normal subjects, 37 patients with HC, and 48 survivors of myocardial infarction (MI). A set of 10 consecutive electrocardiograms was evaluated automatically in each subject using QT Guard software (Marquette Medical Systems, Milwaukee, Wisc.).

Results: In patients with HC, all intervals were significantly prolonged compared with normals (p <0.001 for QT and QTp; p <0.04 for TpTc); in survivors of MI, this was true for the maximum QT and QTp intervals (p <0.05). A strong linear correlation between QT, QTp, and RR intervals was observed in normals and in patients with MI and HC (r = 0.65–0.59, 0.82–0.77, 0.79–0.74, respectively, p <0.0001). TpTc interval only showed a weak correlation with heart rate in normals (r = 0.24, p <0.05) and was rate‐independent in both patient groups (p = NS). Compared with normals, the slopes of QT/RR and QTp/RR regression lines were significantly steeper in patients with MI and HC (0.0990–0.0883, 0.1597–0.1551, 0.1653–0.1486, respectively). Regression lines were neither parallel nor identical between normals and patients (T> 1.96, Z> 3.07). There was no difference in steepness for TpTeR/RR lines between groups (0.0110, 0.0076, 0.0163, respectively). TpTe/QTp ratio was similar in normals and in patients with MI and HC (0.30 ± 0.03, 0.31 ± 0.07, 0.30 ± 0.04, respectively), in the absence of any correlation between QTp and TpTe intervals, suggesting disproportional prolongation of both components of QT interval.

Conclusion: Compared with normals, a progressive increase in QT and QTp intervals at slower heart rates in patients with MI and HC may indicate an enhanced variability of the early ventricular repolarization and may be one of the mechanisms of arrhythmogenesis.
Evaluation of endothelial function in hypertensive elderly patients by high‐resolution ultrasonography
Authors: Wang Xin‐Fang , Deng You‐Bin , Zhang Qing‐Ping , Li Chun‐Lei , Zhang You‐Gen , Le Gui‐Rong
Published: February 2009

Background:Multiple investigations, both in experimental models and in middle‐aged patients with essential hypertension, demonstrate impaired endothelium‐dependent vasodilatation.

Hypothesis:We attempted to determine whether hypertension still exerts additional negative effect on endothelial function of large arteries in hypertensive elderly patients who may already be affected by endothelial dysfunction due to aging.

Methods:We compared 13 elderly patients with hypertension [69 ± 9 years, (mean ± standard deviation)] with 13 matched healthy elderly subjects (72 ± 6 years) as controls. Using high‐resolution vascular ultrasound, we measured brachial artery responses to reactive hyperemia (with increased flow causing endothelium‐dependent dilatation) and sublingual nitroglycerin (causing endothelium‐independent dilatation).

Results:Flow‐mediated dilatation correlated inversely with age (r = –0.60, p = 0.03) in the controls. Flow‐mediated dilatation was significantly impaired in hypertensive elderly patients (6.7 ± 3.3 vs. 13.3 ± 1.8% in controls, p<0.0001). No significant difference could be found in nitroglycerin‐induced dilatation between controls (12.1 ± 4.9%) and hypertensive elderly patients (10.2 ± 6.8%, p=0.5). On multivariate analysis, flow‐mediated dilatation in hypertensive elderly patients was inversely related to aging (r = –0.37, p = 0.04) and mean blood pressure (r = –0.57, p = 0.03).

Conclusions:Our study showed decreased flow‐mediated dilatation with aging even in the healthy controls, and further decline in flow‐mediated dilatation in hypertensive elderly patients compared with controls. This impairment of flow‐mediated dilatation in hypertensive elderly patients was related to age and mean blood pressure, indicating that aging and hypertension may independently impair endothelial function in the brachial artery of these patients.
The use of atropine for facilitation of direct current cardioversion from atrial fibrillation—results of a pilot study
Authors: Sutton A. G. C. , Khurana C. , Hall J. A. , De Belder M.A. , Davies A.
Published: February 2009

Background:The importance of the role of the autonomic nervous system (ANS) in the initiation and propagation of atrial fibrillation has been demonstrated in the condition of paroxysmal atrial fibrillation. However, the role of the ANS in patients with chronic atrial fibrillation is less clear. Some patients with chronic atrial fibrillation are resistant to the standard techniques of direct current (DC) cardioversion.

Hypothesis:We sought to investigate whether excessive vagal tone might prevent the restoration of sinus rhythm and to establish that the abolition of vagal tone using intravenous atropine will facilitate DC cardioversion in patients with atrial fibrillation who are resistant to the standard cardioversion techniques.

Methods:Beginning in August 1994, a change in the protocol for elective DC cardioversion of atrial fibrillation was made to include the use of intravenous atropine for patients resistant to the standard techniques of DC cardioversion.

Results:Over a 2‐year period, 140 elective cardioversions were performed for atrial fibrillation. Sinus rhythm could not be restored on 31 occasions. Intravenous atropine prior to a further 360 J shock with paddles in the anteroposterior position allowed sinus rhythm to be restored on nine occasions. Patients with successful cardioversion after atropine had significantly better left ventricular function than those who remained in atrial fibrillation (p = 0.001) as well as a tendency toward a smaller left atrium.

Conclusion:This study suggests that high vagal tone, which is dominant in patients with structurally normal hearts, may prevent the termination of atrial fibrillation by standard techniques of DC cardioversion, and that the abolition of high vagal tone by atropine facilitates the restoration of sinus rhythm.
Acute myocardial infarction following sildenafil citrate (viagra®) intake in a nitrate‐free patient
Authors: Porter Avital , Mager Aviv , Birnbaum Yochai , Strasberg Boris , Sclarovsky Samuel , Rechavia Eldad
Published: February 2009

Since its introduction to the market in March 1997, sildenafil acetate (Viagra®) has been prescribed to 1.7 million people. Sixteen men who were taking the drug have died, 7 of them during or soon after sexual activity. Most of these data have been derived from the media and not from the scientific literature. There is a general impression that cardiovascular complications of sildenafil occur mainly when the drug is taken concomitantly with nitrates. We describe a 65‐year‐old man with known coronary artery disease who had an acute myocardial infarction shortly after taking sildenafil and engaging in sexual activity. The patient had not been using nitrates. We suggest that the emotional arousal induced by Viagra, followed by the heavy physical exertion during sexual activity, triggers plaque rupture that leads to acute myocardial infarction.
Methods used to interpret the 12‐lead electrocardiogram: Pattern memorization versus the use of vector concepts
Authors: Hurst J. Willis
Published: February 2009

This article extols the value of using Grant's approach to the interpretation of electrocardiograms (ECGs). The essay includes a discussion on how people learn and emphasizes the difference in memorizing information, thinking, and learning. Simply stated, the brains of most people are not designed to memorize countless numbers of ECG patterns. Accordingly, the essay supports the view that a method of interpretation must be used, and the reader is encouraged to use basic principles of electrocardiography, including vector concepts, to interpret each ECG.
Selective estrogen receptor modulators—A new age of estrogens in cardiovascular disease?
Authors: Guzzo Joseph A.
Published: February 2009

A large body of evidence suggests hormone replacement therapy (HRT) reduces cardiovascular risk in postmenopausal women. It is, however, associated with serious side effects, such as increased risk of breast and endometrial cancer. This has likely caused uneasiness among both women and health care providers. A new class of compounds, called selective estrogen receptor modulators (SERMs), have emerged. Through their interactions at the estrogen receptor level they have become a class of compounds distinct from estrogen. While they share similar effects with estrogen on such factors as lipid profile and bone density, they affect other tissues differently. Specifically, they do not induce endometrial hyperplasia and are therefore not associated with endometrial cancer. In vitro studies have also shown that they inhibit lipoprotein oxidation and vascular smooth muscle cell proliferation. The cumulative effects of these compounds may prove quite beneficial in reducing cardiovascular risk in postmenopausal women while avoiding serious side effects. This may, in turn, ease much of the anxiety surrounding the issue of HRT. Clinical trials are presently being conducted to evaluate the effectiveness of raloxifene, a SERM, on cardiovascular risk reduction in postmenopausal women.
Dipyridamole‐Induced reversible Thallium‐201 defect in patients with vasospastic angina and nearly normal coronary arteries
Authors: Fujita Hideki , Yamabe Hiroshi , Yokoyama Mitsuhiro
Published: February 2009

Background: Dipyridamole is a vasodilator of resistance vessels and has no vasoconstrictive effect on large coronary arteries.

Hypothesis: The present study used dipyridamole thallium‐201 (201Tl) scintigraphy to clarify the role of microvasculature in coronary flow limitation in patients with vasospastic angina and normal coronary arteries.

Methods: Sixteen patients underwent dipyridamole and exercise 201Tl scintigraphy and provocative coronary angiography with acetylcholine. All patients showed coronary spasm (>90% vasoconstriction concomitant with ST change) in at least one vessel.

Results: Dipyridamole or exercise caused only ST depression despite the ST elevation observed at spontaneous attack. Dipyridamole 201Tl scintigraphy demonstrated the reversible defects (11 cases), as did exercise 201Tl scintigraphy (13 cases). The region of 201Tl defect was not always consistent with the territories of angiographically depicted vasospastic arteries. Basal coronary tone, assessed by percentage of diameter change of epicardial arteries from baseline to isosorbide dinitrate administration, did not differ between the positive and the negative defect regions.

Conclusion: These results support the hypothesis that, in addition to epicardial coronary spasm, the dysfunction of microvasculature is responsible for abnormal coronary perfusion in the subgroup of patients with vasospastic angina and normal coronary arteries.
Incidence and significance of profound hypotension during dobutamine stress echocardiography
Authors: Dhond Milind R. , Whitley Teresa B. , Singh Satnam , Nguyen Thanh T. , Bommer William J.
Published: February 2009

Background: Mild hypotension (drops of systolic blood pressure of ≥20 mmHg) occurs in 14‐‐38% of dobutamine stress echo (DSE) and carries a good prognosis for subsequent cardiac events. The incidence and significance of more profound hypotension (PH) (≥ 50mmHg) is unknown.

Hypothesis: The aim of the study was to determine the incidence of PH during DSE and its prognosis for subsequent cardiac events.

Methods: We reviewed 617 DSE performed at our institution between 1992 and 1996 and identified two DSE subgroups. The first group (PH group) consisted of all patients with PH during DSE. A second group was selected with baseline characteristics similar to the PH group but without PH during DSE (non‐PH group). Follow‐up was by a physician chart review and direct telephone contact. Cardiac event rates were determined for hard [myocardial infarction (MI), or cardiac death] and soft (angina, congestive heart failure, coronary angioplasty, or coronary bypass surgery) events occurring after the DSE.

Results: Of the 617 DSE performed, 16 (3%) patients developed PH (PH group) during DSE, with 13 showing no inducible ischemia. The hard and soft cardiac event rate in this 13 PH group was 46% (mean follow‐up of 28.7 ± 18 months). Of the non‐PH group, 32 patients had a negative DSE with a coronary event rate of 12.5%. Profound hypotension correlated with a significantly higher cardiac event rate (p < 0.02).

Conclusions: The incidence of PH during DSE is low (3%) and appears to predict a worse prognosis for subsequent cardiac events.
Tachycardia‐dependent right bundle‐branch block with supernormal conduction
Authors: Katoh Takakazu , Kinoshita Shinji , Oyama Yohtaro , Tsujimura Yoshinori , Sasaki Yoshihiko
Published: February 2009

This paper reports the case of a 76‐year‐old man in whom atrial flutter with varying atrioventricular block and intermittent right bundle‐branch block was found. This is the first report on tachycardia‐dependent right bundle‐branch block associated with supernormal conduction in a case of atrial flutter. When an impulse is conducted to the ventricles beyond 0.72 s after a QRS complex of right bundle‐branch block configuration, the impulse falls after the abnormally long effective refractory period of the right bundle branch and passes through the right bundle branch. When the conducted impulse occurs within 0.72 s after a QRS complex of right bundle‐branch block configuration, the impulse usually falls in the refractory period and is blocked in the right bundle branch; however, only when the impulse occurs 0.48 or 0.49 s after that does it fall in the supernormal period and passes through the right bundle branch. The findings in the present report strengthen our previous suggestion that the presence of supernormal conduction plays an important role in the initiation of reentrant ventricular tachycardia.
Five‐year mortality in patients with acute chest pain in relation to smoking habits
Authors: Herlitz Johan , Karlson Björn W. , Sjölin Margareta , Lindqvist Jonny , Karlsson Thomas , Caidahl Kenneth
Published: February 2009

Background: Smoking is one of the major risk indicators for development of coronary artery disease, and smokers develop acute myocardial infarction (AMI) approximately a decade earlier than nonsmokers. In smokers with established coronary artery disease, quitting smoking has been associated with a more favorable prognosis. However, most of these studies comprised younger patients, the majority of whom were males.

Hypothesis: The purpose of the study was to determine mortality, mode of death, and risk indicators of death in relation to smoking habits among consecutive patients admitted to the emergency department with acute chest pain.

Methods: In all, 4,553 patients admitted with acute chest pain to the emergency department at Sahlgrenska University Hospital during a period of 21 months were included in the analyses and were prospectively followed for 5 years.

Results: Of these patients, 36% admitted current smoking. They were younger and had a lower prevalence of previous cardiovascular diseases than did nonsmokers. The 5‐year mortality was 19.4% among smokers and 24.9% among non‐smokers (p<0.0001). However, when adjusting for difference in age, smoking was associated with an increased risk [relative risk (RR) 1.51; 95% confidence interval (CI) 1.32–1.74; p< 0.0001]. Among patients presenting originally with chest pain, the increased mortality for smokers was more pronounced in patients with non‐acute than acute myocardial infarction (AMI). Among patients who died, death in smokers was less frequently associated with new‐onset myocardial infarction (MI) and congestive heart failure. Among those who smoked at onset of symptoms and were alive 1 year later, 25% had stopped smoking. Patients with a confirmed AMI who continued smoking 1 year after onset of symptoms had a higher mortality (28.4%) during the subsequent 4 years than patients who stopped smoking (15.2%; p = 0.049).

Conclusion: In consecutive patients admitted to the emergency department with acute chest pain, current smoking was significantly associated with an increased risk of death during 5 years of follow‐up. Among patients who died, death in smokers was less frequently associated with new‐onset MI and congestive heart failure than was death in nonsmokers.
Effects of early captopril therapy after myocardial infarction on the incidence of late potentials
Authors: Chiladakis John A. , Karapanos George , Agelopoulos George , Alexopoulos Dimitris , Manolis Antonis S.
Published: February 2009

Background: Late potentials (LP) on signal‐averaged electrocardiography (SAECG), recorded 6 to 30 days after an acute myocardial infarction (AMI), identify patients at risk for late arrhythmic events. Angiotensin‐converting enzyme (ACE) inhibitors have been shown to reduce ventricular remodeling and cardiovascular mortality after AMI.

Hypothesis: The aim of this study was to investigate the effect of early (< 24 h) administration of captopril on the presence of LP on Days 6–30 after AMI.

Methods: The study included 117 patients with a first AMI; 63 patients (53 men and 10 women, aged 59±12 years), 35 with an anterior and 28 with an inferior AMI (44 thrombolyzed), received early captopril therapy. The control group consisted of 54 age‐matched patients (39 men and 15 women, aged 60 ± 12 years), 19 with an anterior and 35 with an inferior AMI (31 thrombolyzed, p = NS), who did not receive early therapy with an ACE inhibitor. The mean left ventricular ejection fraction was similar in both groups (48 vs. 46%). Time domain analysis of SAECG was performed using a band‐pass filter of 40–250 Hz. Late potentials were considered present if any two of three criteria were met: (1) Filtered QRS duration (QRSD) > 114 ms, (2) root‐mean‐square voltage of the last 40 ms of the QRS complex (RMS) > 20 m̈V, and (3) duration of low amplitude (< 40 m̈V) signal of the terminal portion of the QRS (LAS) > 38 ms.

Results: In the two groups of patients there were no differences in mean values of SAECG parameters. No patient was receiving any antiarrhythmic drugs. In the captopril group LPs were present in 9 of 63 patients (14%) and in the control group in 17 of 54 patients (31 %) (p =0.046). There was no difference in the number of patients with a patent infarct‐related artery in the two groups (76 vs. 59%).

Conclusion: Captopril treatment early after an AMI reduces the incidence of LPs recorded on Days 6–30 and may thus favorably affect the arrhythmogenic substrate.
Refractory vasospasm with a malignant course
Authors: Kumar Ananth , Chandna Harish , Santhanam Vimala , Denes Pablo
Published: February 2009

We present a patient with two rare disorders, recurrent vasospastic angina leading to cardiac transplant and acute aortic occlusion. The patient had recurrent episodes of coronary vasospasm presenting with unstable angina, acute myocardial infarction, and sudden cardiac death in spite of adequate therapy with nitrates and calcium‐channel blockers. He went on to have a cardiac transplant. The patient later presented with acute aortic occlusion with concomitant renal and mesenteric artery spasm. The circumstances of the presentation raise the possibility of a generalized vasospastic predisposition that is responsible for both events. Smoking, the only known major risk factor other than atherosclerosis, was noted to be temporally related to both events in our patient.
Echocardiography of the coronary sinus in adults
Authors: D'Cruz Ivan A. , Shala M. Bashar , Johns Cameila
Published: February 2009

The coronary sinus (CS) is a small tubular structure just above the posterior left atrioventricular junction. The CS can be imaged in several different echocardiographic views. Using zoom M‐mode recordings of the CS in apical two‐chamber view, CS caliber can be sharply imaged and easily measured during different phases of the cardiac cycle. We have recently shown that the CS narrows during atrial contraction in persons with sinus rhythm, but does not narrow at all if atrial fibrillation is present. Attenuation of CS narrowing occurs in patients with congestive heart failure and inferior vena cava plethora. Maximal CS caliber occurs during ventricular systole. Patients with poor left ventricular systolic function show mild CS dilatation. Greater CS dilatation is present in patients with persistent left superior vena cava, and huge dilatation when this anomaly is accompanied by absence of a right superior vena cava. Injection of sonicated saline into a left and then a right arm vein is diagnostically useful in confirming these two venous anomalies. Pulsed‐wave Doppler of the CS can be recorded in the parasternal right heart inflow view. From this and from the CS cross‐section area it may be possible to estimate coronary blood flow.
Atrial fibrillation independently prolongs hospital stay after coronary artery bypass surgery
Authors: Tamis Jacqueline E. , Steinberg Jonathan S.
Published: February 2009

Background: Atrial fibrillation (AF) is the most common arrhythmia occurring in patients after coronary artery bypass surgery (CABG).

Hypothesis: The purpose of this study was to determine whether AF independently prolonged postoperative length of stay (LOS).

Methods: Consecutive patients undergoing elective CABG were identified. Baseline clinical variables, postoperative course including the development of AF, and postoperative LOS were recorded.

Results: In all, 216 patients (aged 61 ± 13 years) were examined. Postoperative LOS was 11.3 ± 6.4 days (median LOS = 9 days). Fifty‐five patients (25%) developed AF. Among 16 variables examined, the univariate predictors of LOS included age (p < 0.001), preoperative left ventricular ejection fraction (p < 0.001), absence of a prior smoking history (p < 0.05), bypass limited to venous conduits (p < 0.001), postoperative AF (p < 0.001), and the occurrence of a postoperative event (p < 0.001). Length of stay for patients who developed AF was significantly longer than that for patients who did not (15.1 ± 9.0 vs. 10.0 ± 4.6 days, p < 0.001). After adjusting for other significant variables, the occurrence of AF after CABG independently prolonged LOS: patients who developed AF stayed 3.2 ± 1.7 days longer than patients who did not (p < 0.001).

Conclusions: Atrial fibrillation lengthens hospital stay after CABG, and its effect is independent of other important variables. Identification of patients who are at risk for AF and successful treatment to prevent AF will likely contribute to major reductions in consumption of health care resources in patients with CABG.
Stability of the noninvasive baroreflex sensitivity assessment using cross‐spectral analysis of heart rate and arterial blood pressure variabilities
Authors: Wichterle Dan , Melenovsky Vojtech , Necasova Lucie , Kautzner Josef , Malik Marek
Published: February 2009

Background: Depressed baroreflex sensitivity (BRS), usually estimated using the invasive phenylephrine method or the nitroprusside test, is significantly and independently associated with an increased risk of malignant ventricular arrhythmias and sudden cardiac death in patients surviving acute myocardial infarction. Several investigators have compared the standard phenylephrine test and different noninvasive methods.

Hypothesis: This study evaluated the influence of different body positions with different breathing regimes on cross‐spectral baroreflex indices (coherence between the spectral densities of blood pressure and cardiac cycle variabilities) in both low‐ and high‐frequency bands.

Methods: The data were obtained in 103 patients (73 males, aged 53 ± 12 years) with coronary artery disease and/or hypertension. Simultaneous electrocardiographic and noninvasive blood pressure recordings were obtained in each subject in both supine and sitting positions during both spontaneous and slow and fast controlled respiration (0.1 and 0.33 Hz).

Results: The results show a significant bias and disagreement between noninvasive baroreflex sensitivity (BRS) indices. The mean values of the baroreflex in low frequency ranged from 5.0 ± 5.3 to 10.1 ± 7.9 ms/mmHg, while in high frequency, the mean values ranged from 6.6 ± 6.1 to 10.1 ± 7.9 ms/mmHg. The limits of agreement ranged from ± 1.7 to ± 4.1 ms/mmHg with bias from ‐1.0 to + 0.7 ms/mmHg.

Conclusion: A comprehensive comparison of different methods shows that BRS estimated in low‐frequency band in sitting position during spontaneous respiration is the most representative part of the global baroreflex gain.
Acute management of atrial fibrillation and atrial flutter in the critical care unit: shouLd it be ibutilide?
Authors: Varriale Philip , Sedighi Abdollah
Published: February 2009

Background:Ibutilide is currently indicated for the rapid conversion of atrial fibrillation (Afb) or atrial flutter (Afl) of recent onset but limited to patients who are hemodynamically stable and without symptomatic cardiovascular conditions.

Hypothesis:The study was undertaken to assess the efficacy and safety of ibutilide in patients with Afb or Afl associated with acute cardiovascular‐medical disorders and in patients receiving prior selective antiarrhythmic drug therapy.

Methods:The study included 34 patients, mean age 75 ± 16.3 years, with Afb (n = 25) or Afl (n = 9) having a variety of disorders, for example, congestive heart failure, unstable angina, borderline hypotension, respiratory failure, and chronic renal failure. Prior antiarrhythmic drugs consisted of propafenone (n = 5) or amiodarone (n = 3). Eligibility for cardioversion was established with appropriate anticoagulation or transesophageal echocardiography findings. Ibutilide was given as up to two 10 min infusions of 1 mg separated by 10 min.

Results:The overall conversion rate after ibutilide was 79.4% (27/34 patients): 80% for Afb and 78% for Afl. More than 90% converted within 1 h of treatment. A high conversion rate of 92% resulted in those with an arrhythmia duration of ≤ 1 week. All eight patients with prior antiarrhythmic therapy converted to sinus rhythm. The average baseline QTc interval for all patients increased 17.1% (397 ± 63.3 to 465 ± 60.2 ms) at 30 min. For eight patients (including four who received prior antiarrhythmic drugs), QTc interval prolongation ≥ 500 ms was associated with nearly half the entire incidence of arrhythmic events. Proarrhythmia, the exclusive adverse effect, consisted of ventricular extrasystoles (n = 10) and nonsustained monomorphic ventricular tachycardia (VT) (n = 2) managed with intravenous MgSO4, and sustained polymorphic VT (n = 1) requiring electrical cardioversion.

Conclusion:Ibutilide is an effective and well tolerated drug for the rapid termination of Afb or Afl of recent onset associated with symptomatic and/or hemodynamically unstable disorders, and it is most efficacious (≥ 90%) when the atrial arrhythmia is ≤ 1 week in duration. Proarrhythmic events are readily manageable in a monitored unit with access to appropriate treatment.
Myocardial stunning in hyperthyroidism
Authors: Pereira Naveen , William Dec G. , Choo Joseph , Hajjar Roger , Parisi Alfred , Gordon Paul C.
Published: February 2009

The cases of two patients with hyperthyroidism and acute left ventricular (LV) dysfunction with segmental wall motion abnormalities resulting in heart failure are reported. Both had electrocardiographic changes mimicking ischemic coronary artery disease. Treatment with antithyroid medications, beta blockers, and angiotensin‐converting enzyme inhibitors rapidly restored LV function. The rapid reversibility suggests a role for myocardial stunning, an important entity to recognize in hyperthyroidism since this form of LV dysfunction can be reversed with appropriate treatment.
High‐output heart failure resulting from a remote traumatic aorto‐caval fistula: Diagnosis by echocardiography
Authors: Abreo Gerard , Lenihan Daniel J. , Nguyen Peter , Runge Marschall S.
Published: February 2009

Congestive heart failure (CHF) due to high output states is known to occur in a variety of systemic illnesses and in patients with arterial‐venous fistulas. This paper reports the case of a 45‐year‐old man admitted to the emergency room with a diagnosis of new onset atrial fibrillation and CHF, whose past medical history was not significant except for a gunshot wound to his abdomen 22 years previously. The etiology of his CHF together with the cardiomegaly and hyperdynamic left ventricular systolic function was unknown. A subcostal view routinely done during transthoracic echocardiography revealed a severely dilated inferior vena cava and the presence of an aorto‐caval fistula by color doppler. The patient underwent successful corrective repair with dramatic improvement in symptoms and resolution of the atrial fibrillation, and cardiac size returned to normal. This rare case emphasizes that patients with refractory CHF must be closely examined with particular attention to palpation and auscultation over all scars, irrespective of the duration since any traumatic or surgical event.
The implantable cardioverter‐defibrillator
Authors: Leon Greene H.
Published: February 2009

Ventricular arrhythmias remain a major cause of cardiovascular mortality. Therapy for serious ventricular arrhythmias has evolved over the past decade, from treatment primarily with antiarrhythmic drugs to implanted devices. The implantable cardioverter‐defibrillator (ICD) is the best therapy for patients who have experienced an episode of ventricular fibrillation not accompanied by an acute myocardial infarction or other transient or reversible cause. It is also superior therapy in patients with sustained ventricular tachycardia (VT) causing syncope or hemodynamic compromise. Controlled clinical trials have confirmed the utility of these devices. As primary prevention, the ICD is superior to conventional antiarrhythmic drug therapy in patients who have survived a myocardial infarction and who have spontaneous, nonsustained ventricular tachycardia, a low ejection fraction, inducible VT at electrophysiologic study, and whose VT is not suppressed by procainamide. The effect of the ICD on survival of other patient populations remains to be proven. The device is costly, but its price is generally accepted to be reasonable. The ICD has been a major advance in the treatment of ventricular arrhythmias.
Impact of left ventricular size on pharmacologic reverse remodeling in heart failure
Authors: Barry Levine T. , Levine Arlene B. , Bolenbaug Janet , Stomel Robert J.
Published: February 2009

Background and hypothesis: Although medical therapy may normalize echocardiographic left ventricular (LV) systolic function in selected patients with cardiomyopathy, other patients experience no change or a further deterioration in heart failure remodeling. Our aim was to determine what clinical or echocardiographic parameters predict a beneficial therapeutic response.

Methods: We prospectively followed biannual clinical and echocardiographic assessments in 215 patients. Forty‐six of these patients (“Nonresponders”) experienced no change or a decline in LV ejection fraction at 6 months. Of the 148 patients who improved LV function, 21 (“Responders”) normalized LV systolic function at 6 months. Only Responders (n = 21) and Nonresponders (n = 46) were compared.

Results: On average, these 67 patients were 54 ± 12 years old with 4.5 ± 3.3 years of heart failure. At 6 months, following uptitration of angiotensin‐converting enzyme inhibitors and nitrates, Responder LV ejection fraction rose from 22 ± 6 to 50 ± 5% with improvement in New York Heart Association classification (2.6 ± 0.8 to 1.5 ± 0.8, p = 0.001). These patients had significantly more favorable clinical and echocardiographic outcomes versus Nonresponders despite comparable medical therapy. All baseline demographic, clinical, and echocardiographic variables were equivalent, except for initial LV end‐diastolic diameter which differentiated Nonresponders (7.1 ± 0.7 cm) from Responders (6.1 ± 0.8 cm), p = 0.007.

Conclusion: Thus, although heart failure therapy improves LV systolic function in a majority of patients, with normalization in up to 10% of patients, significant LV enlargement may render remodeling unresponsive to pharmacologic intervention, with a potential future need for alternative mechanical or surgical intervention.
Acute myocardial infarction—A late complication of intracoronary stent placement
Authors: Danenberg Haim D. , Lotan Chaim , Hasin Yonathan , Gotsman Mervyn S. , Rozenman Yoseph
Published: February 2009

Background: Myocardial infarction (MI) as the first indication of postangioplasty restenosis is extremely rare, and it has been speculated that the fibroproliferative restenotic lesion is less likely to undergo plaque rupture than the lipid ‐laden native atherosclerotic lesion.

Hypothesis: The present study was designed to examine whether intracoronary stent implantation affects this course.

Methods: In all, 994 consecutive patients who underwent angioplasty and intracoronary stent implantation in our hospital were reviewed retrospectively for the occurrence of MI.

Results: Eight patients (0.8%), all male and hypertensive, aged 33–83 years, presented with an MI due to stent occlusion more than 30 days following stenting (range: 35–398 days). In two patients, MI occurred 3 and 5 h, respectively, following completion of a maximal high‐level exercise test that was negative for ischemia. Angiography revealed complete occlusion or significant stenosis of the stent in all eight patients, with an obvious intimal dissection in either edge of the stent in six patients. Except for gender and hypertension, no correlation was found with other risk factors, vessel involved, initial angiographic results, or with stent design, diameter, or length.

Conclusions: Myocardial infarction as a late complication of successful stent implantation occurred in 0.8% of our patients. This is only the lower bound of the estimated frequency for such an event. We hypothesize that the transition point between the relatively fixed stent and the normal artery is exposed to high deformation stress which makes it vulnerable to rupture and dissection. Strenuous exercise and hypertension may increase the deformation stress and the risk of intimal rupture.
Hyperthyroid heart disease
Authors: Fadel Bahaa M. , Ellahham Samer , Lindsay Joseph , Ringel Matthew D. , Wartofsky Leonard , Burman Kenneth D.
Published: February 2009

The heart is an organ sensitive to the action of thyroid hormone, and measurable changes in cardiac performance are detected with small variations in thyroid hormone serum concentrations. Most patients with hyperthyroidism experience cardiovascular manifestations, and the most serious complications of hyperthyroidism occur as a result of cardiac involvement. Recent studies provide important insights into the molecular pathways that mediate the action of thyroid hormone on the heart and allow a better understanding of the mechanisms that underlie the hemodynamic and clinical manifestations of hyperthyroidism. Several cardiovascular conditions and drugs can interfere with thyroid hormone levels and may pose a difficulty in interpretation of laboratory data in patients with suspected thyroid heart disease. The focus of this report is a review of the current knowledge of thyroid hormone action on the heart and the clinical and hemodynamic laboratory findings as well as therapeutic management of patients with hyperthyroid heart disease.
Low‐dose dobutamine radionuclide ventriculography for prediction of myocardial viability: Quantitative analysis of regional left ventricular function
Authors: Takeyasu Noriyuki , Watanabe Shigeyuki , Yamaguchi Iwao , Eda Kazuhiko , Toyama Masahiro , Sakamoto Kazuhiko , Saito Takumi , Yamanouchi Takayoshi , Masuoka Takeshi , Ajisaka Ryuichi , Takeda Tohru , Itai Yuji , Sugishita Yasuro
Published: February 2009

Background: It is important to distinguish viable myocardium from necrotic tissue in order to decide upon therapy in patients with ischemic heart disease.

Hypothesis: We verified the hypothesis that quantitative analysis of regional left ventricular function using low‐dose dobutamine radionuclide ventriculography (RNV) can sensitively predict myocardial viability and compared its usefulness with thallium‐201 (201Tl) single‐photon emission computed tomography (201Tl‐SPECT).

Methods: Radionuclide ventriculography at rest and during low‐dose dobutamine infusion (5 m̈g/kg/min), 201Tl‐SPECT, and coronary angiography were performed in 51 subjects with severe ischemia‐related stenosis of coronary arteries and 3 subjects without coronary artery disease. 201Tl uptake was assessed as normal (control), low perfusion (LP), or defect. We compared the response of regional function to dobutamine with the regional 201Tl uptake. The accuracy of both methods for identifying viable myocardium was investigated in 17 patients who underwent successful coronary revascularization, with a resulting improvement in wall motion.

Results: The increase in regional ejection fraction (δr‐EF) in response to dobutamine was significantly greater in the control (12 ± 6%) and LP (16 ± 11%) regions than in the defect (5 ± 10%) regions. The increase in one‐third regional ejection fraction (δr‐1/3EF) was also significantly higher in the control (14 ± 7%) and LP (10 ± 8%) regions than in the defect regions (5 ± 6%). We defined myocardial viability as a δr‐EF > 5% or a δr‐1/3EF > 2%. The sensitivity and specificity of the δr‐EF for identification of myocardial viability were 91.4 and 55.5%, respectively. The sensitivity and specificity of the δr‐1/3EF were 91.4 and 66.6%, respectively; the corresponding values for 201TlSPECT were 74.2 and 77.8%.

Conclusion: Low‐dose dobutamine RNV with quantitative analysis of regional left ventricular function was more sensitive for identification of viable myocardium than 201Tl‐SPECT.
Metabolic and clinical effects of oral magnesium supplementation in furosemide‐treated patients with severe congestive heart failure
Authors: Cohen Natan , Alon Irena , Almoznino‐Sarafian Dorit , Weissgarten Joshua , Gorelik Oleg , Berman Sylvia , Zaidenstein Ronit , Golik Ahuva , Modai David
Published: February 2009

Background:Magnesium depletion and hypomagnesemia are common among furosemide‐treated patients with chronic congestive heart failure.

Hypothesis:This investigation evaluated clinical and metabolic effects of oral magnesium supplementation.

Methods:Ten patients with severe congestive heart failure maintained on high dose furosemide (≥ 80 mg/day) received a supplement of oral magnesium citrate 300 mg/daily for 30 days. Clinical parameters were followed, and peripheral blood mononuclear cell magnesium and zinc content, serum and urine magnesium, potassium, zinc, calcium, phosphorus, and creatinine were assessed.

Results:Peripheral blood mononuclear cell magnesium content and serum potassium rose significantly at the end of the study (2.09 ± 1.89 to 3.99 ± 2.26 m̈g/mg cell protein, p< 0.05, and 4.17 ± 0.38 to 4.39 ± 0.27 mEq/l, p <0.05, respectively), while the other parameters remained unchanged.

Conclusion:In some of these patients, oral magnesium supplementation is effective in achieving substantial increments in intracellular magnesium and serum potassium which, in turn, may have cardioprotective effects.
Treatment of hypertension with perindopril reduces plasma atrial natriuretic peptide levels, left ventricular mass, and improves echocardiographic parameters of diastolic function
Authors: Yalçin Fatih , Garcia Mario J. , Thomas James D. , Aksoy Fatma G. , Muderrisoglu Haldun , Sabah Irfan
Published: February 2009

Background: Hypertension is a major independent risk factor for cardiac deaths, and diastolic dysfunction is a usual finding during the course of this disease.

Hypothesis: This study was designed to investigate the effects of chronic therapy with perindopril on left ventricular (LV) mass, left atrial size, diastolic function, and plasma level of atrial natriuretic peptide (ANP) in patients with hypertension.

Methods: Twenty four patients who had not been previously taking any antihypertensive medication and without prior history of angina pectoris, myocardial infarction, congestive heart failure, dysrhythmias, valvular heart disease, or systemic illnesses received 4–8 mg/day of perindopril orally. Echocardiographic studies were acquired at baseline and 6 months after the initiation of therapy.

Results: Systolic and diastolic blood pressure decreased from 174 ± 19.7 and 107.5 ± 7.8 mmHg to 134±10.6 and 82±6.7 mmHg, respectively (p <0.001). Left ventricular mass decreased from 252.4±8.3 to 205.7±7.08 g and left atrial volume from 20.4±5.1 to 17.6±5.2 ml, respectively (p <0.001). Transmitral Doppler early and atrial filling velocity ratio (E/A) increased from 0.69 ± 0.06 to 0.92 ± 0.05 m/s and plasma ANP level decreased from 71.9 ± 11.7 to 35.3 ± 7.8 pg/ml (p <0.001). Reduction of LV mass correlated positively with a reduction in ANP levels (r = 0.66, p <0.0005).

Conclusions: Perindopril caused a significant reduction of LV mass, left atrial volume, and plasma ANP levels, as well as improvement in Doppler parameters of LV filling in this group of patients with hypertension.
A comparison of brachial artery row‐mediated vasodilation using upper and lower arm arterial occlusion in subjects with and without coronary risk factors
Authors: Vogel Robert A. , Corretti Mary C. , Plotnick Gary D.
Published: February 2009

Background: The ultrasound assessment of brachial artery flow‐mediated vasodilation provides a noninvasive means for measuring endothelial function. The test is performed using either upper or lower arm blood pressure cuff arterial occlusion to induce hyperemia. Upper arm occlusion produces a greater hyperemic stimulus. Brachial artery flow‐mediated vasodilation is abnormal in the presence of coronary risk factors.

Hypothesis: The study sought to compare the ability of the upper and lower arm occlusion techniques to differentiate endothelial function in subjects with and without risk factors.

Methods: We measured brachial artery flow‐mediated vasodilation in 20 subjects, 10 without and 10 with a single risk factor (hypertension, hypercholesterolemia, or cigarette smoking) using both the upper and lower arm occlusion techniques (5 min blood pressure cuff occlusion). Using 11 MHz ultrasound, Doppler blood flow velocities were measured before and immediately after cuff deflation. Brachial artery vasodilation was measured 1 min after cuff deflation, compared with baseline, and expressed as a percent increase.

Results: The immediately postocclusion hyperemia (% increase in flow) was significantly greater (p<0.01) using the upper versus the lower arm technique in both the normal (530 ± 152 vs. 383 ± 51 %) and the risk factor (583 ± 153 vs. 409 ± 114%) groups. Row‐mediated vasodilation was significantly greater (p < 0.01) using the upper arm versus the lower arm occlusion technique in both the normal (13.4 ± 5.3 vs. 5.6 ± 3.4%) and risk factor (7.9 ± 3.6 vs. 3.9 ± 2.2%) groups. Vasodilation was significantly greater (p < 0.01) in the normal subjects than in the risk factor subjects (13.4 ± 5.3 vs. 7.9 ± 3.6%) using the upper arm technique, but was not statistically different in the two groups using the lower arm technique.

Conclusions: Our study demonstrates that upper arm compared with lower arm cuff occlusion undertaken to induce hyperemia for the assessment of brachial artery flow‐mediated vasodilation results in significantly greater hyperemia and vasodilation. Flow‐mediated vasodilation obtained using the upper arm technique better separates subjects with and without coronary risk factors.