bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reproducibility of the spectral turbulence analysis of the signal‐averaged electrocardiogram
Authors: Vado Antonello , Bruna Claudio , Rossetti Guido , Uslenghi Eugenio 
Published: August 2009

AbstractSpectral turbulence analysis (STA) of the signal‐averaged electrocardiogram (SAECG) is a recently proposed technique to identify patients with ventricular tachycardia as well as patients at risk for arrhythmic events after acute myocardial infarction (MI). The short‐term reproducibility of this technique has been previously reported; our study evaluates the reproducibility of STA by shifting the reference points. Twenty patients with acute MI were recruited. SAECG was recorded 13 days after onset of the acute MI. Unfiltered data were transferred and analyzed by personal computer software for spectral turbulence analysis according to the standard condition; reference points of the segment of interest were shifted from QRS offset −10 ms and QRS onset −10 ms to QRS offset +10 ms and QRS onset +10 ms, step 2 ms. Thus, 10 analyses were computed. Reproducibility of the results was calculated using the coefficient of variation (CV) and the relative error (RE). The reproducibility of the classification (RC) was defined as the percentage of the identical classification compared with the standard segment. CV of the intersegment correlation standard deviation was statistically higher than the other parameters regardless of the lead considered. RE was not different in each parameter and in each lead. RC was > 90% in all parameters, except in spectral entropy which showed an RC > 80%. Reproducibility of the STA introducing a temporal shift in the analyzed segments was high in all considered parameters.
Echocardiographic diagnosis of congential absence of the pericardium in a patient with VATER association defects
Authors: Lu Charles , Ridker Paul M. 
Published: August 2009

AbstractThe VATER association denotes a nonrandom pattern of congential malformations which typically include vertebral defects, anal atresia, tracheo‐esophageal fistula, and radial and renal dysplasia. Vascular anomalies including ventricular septal defect and single umbilical artery have also been described, although the frequency of cardiovascular anomalies in this congenital association is unknown. In this report, we describe a 26‐year‐old patient with several VATER association defects who, in addition, was found to have congenital absence of the left pericardium and an aberrant right subclavian artery.
Electrocardiographic and segmental wall motion abnormalities in pancreatitis mimicking myocardial infarction
Authors: Patel Jayesh , Movahed Assad , Reeves William C. 
Published: August 2009

AbstractTransient electrocardiographic changes in patients with acute cholecystitis, pancreatitis, and pneumonia have been reported in the past.1‐5These changes usually are in the form of T‐wave inversion, ST‐segment depression, and rarely ST‐segment elevation in the absence of coronary artery disease.1‐5To the authors' knowledge, this is the first report documenting both left ventricular segmental wall motion abnormality and electrocardiographic changes of myocardial injury in the presence of acute pancreatitis.
Newer doppler measures of left ventricular diastolic function
Authors: Pai Ramdas G. , Buech Geneen C. C. 
Published: August 2009

AbstractLeft ventricular (LV) diastolic dysfunction is an important cause of heart failure, and recent advances in the application of Doppler techniques allow a semiquantitative assessment of LV diastolic performance. This review discusses the use of Doppler echocardiography in the comprehensive assessment of LV diastolic function and performance in terms of the normal mitral and pulmonary venous flow profiles, their physiologic basis, and alteration in diseased states. There is also a discussion on the newer aspects of mitral flows such as relative durations of mitral A and pulmonary vein AR waves, E‐ and A‐wave propagation inside the LV with their hemodynamic correlates, and derivation of ventricular dP/dt and Tau from the mitral regurgitation velocity profile. Analysis of these flow profiles and the other Doppler measures alluded to above allow one to make a fairly precise hemodynamic assessment of a patient in terms of left atrial pressure, LV relaxation and stiffness and the profile of LV diastolic pressure in terms of pre‐‘a’ wave and ‘a’ wave pressures and ventricular end‐diastolic pressure.
Evidence for a relation between inspired gas mixture and the left ventricular contrast achieved with albunex® in a Canine Model
Authors: Geiser Edward A. , Cunningham Michael S. , Wilson David C. , Buss Daryl D. , Wible James H. , Webb Alistair I. , Yang Mark 
Published: August 2009

AbstractBackground: In a previous experiment, a marked reduction in the right‐and left‐sided contrast effect of Albunex was noted in an intubated animal spontaneously breathing isoflurane in 100% oxygen. The theory suggests that the time course of echogenicity of microbubbles in a liquid is dependent on the pressure and the gradients of dissolved gases. The present set of experiments tested whether the loss of contrast occurs at commonly used therapeutic concentrations of inspired oxygen.Hypothesis: This research tested the hypothesis that the left ventricular (LV) contrast effect achieved with intravenous injection of the ultrasound contrast agent Albunexr̀ is related to the inspired oxygen content.Methods: Intubated dogs were maintained in a spontaneously respiring anesthetic state on isoflurane and mixtures of oxygen (12‐50%) in nitrogen. FIo2 was held steady for 15 min prior to injection of 0.08 ml/kg of Albunex. The contrast effects were recorded from a transthoracic short‐axis view. Left and right ventricular brightness curves were generated from digitized sequences of end‐diastolic frames. The minimum and maximum brightness and area under the time‐brightness curves were determined.Results: The LV maximum brightness and area under the curve showed significant negative correlations (p = <0.004) with the FIo2, while the minimum brightness showed a significant positive correlation (p = < 0.002). No significant correlations were found for the right ventricular brightness parameters.Conclusions: These findings show an important relationship between the FIo2 and loss of the contrast effect of Albunex. This loss occurs at oxygen concentrations in the therapeutic range, but could be overcome by increasing the dose of Albunex. The mechanism is likely related to an outward nitrogen gradient causing a loss of echogenicity. The clinical implication is that patients on supplemental oxygen may require higher doses of Albunex to achieve optimal opacification.
Effects of heart rate on flow velocity of the left atrial appendage in patients with nonvalvular atrial fibrillation
Authors: Noda Toshiyuki , Arakawa Michio , Mrwa Hiroshi , Ito Yoshimi , Kagawa Kensaku , Nishigaki Kazuhiki , Hirakawa Senri , Fujiwara Hisayoshi 
Published: August 2009

AbstractBackground and hypothesis: Flow velocity of the left atrial appendage (LAA) is thought to be important in thrombus formation in association with blood stasis and the development of spontaneous echo contrast. The effects of heart rate on peak flow velocity of the LAA have not been studied in patients with nonvalvular atrial fibrillaton.Methods: Using transesophageal Doppler echocardiography, peak flow velocity of the LAA was measured at the junction between the left atrium and the LAA during left ventricular (LV) systole and diastole in 21 patients with nonvalvular atrial fibrillation. In six cases, the average peak flow velocity of the LAA for 10 consecutive beats with moderately long R‐R intervals (LI beats) was compared with those for 3‐5 consecutive beats with extremely short R‐R intervals (SI bets).Results: Average peak flow velocity of the LAA during LV diastole was significantly higher than that during LV systole (26.5 ± 15.7 vs. 19.3 ± 10.4 cm/s, p<0.01). In SI beats, average peak flow velocity of the LAA was significantly lower than that in LI beats (17.1 ± 12.1 vs. 21.2 ± 12.9 cm/s, p<0.01).Conclusion: An increased heart rate reduced the peak flow velocity of the LAA in patients with nonvalvular atrial fibrillation, which would promote blood stasis in the LAA.
Association of Conventional and Exertional Coronary Heart Disease Risk Factors in 5,000 Apparently Healthy Men
Authors: Davies Bruce , Ashton William D. , Rowlands Derek J. , El‐Sayed Mahmoud , Wallace Philip C. , Duckett Ken , Coley John , Daggett Anne M. 
Published: August 2009

AbstractBackground and hypothesis: The aim of this study was to define the prevalence of previously undetected coronary heart disease among asmptomatic males, aged 30‐65 years, by means of resting and exercise electrocardiography in conjunction with an analysis of conventional and exertional coronary risk factors.Methods: Between January 1985 and December 1989 we examined 5,000 clinically asymptomatic subjects. A detailed case history was obtained for each individual, followed by a complete physical examination, comprehensive blood (including lipid) profile, lung function tests, chest x‐ray, a resting 12‐lead electrocardiogram (ECG), and a maximal treadmill exercise ECG. Whenever possible, on‐line computerized respiratory analysis (Beckman Metabolic Measurement Cart) was carried out during the exercise tests. Conventional and exertional coronary heart disease risk factors were also recorded.Results: A total of 162 persons (3.2%) showed abnormal S‐T segment responses during the exercise or recovery period. Of these, 92 subjects underwent further investigations: coronary angiography (79), 201thallium scanning (13), 201thallium scanning followed by coronary angiography(7). Of the 86 patients who proceeded to cornoary angiography, 19 (22%) had either normal coronary artery anatomy or only insignificant disease. Among the 67 (78%) of patients with significant angiographically demonstrable disease, 26 received coronary artery bypass grafting, 7 underwent coronary angioplasty, and the remainder continued on medical management.Conclusions: These results are discussed in relation to a variety of conventional and exertional coronary risk factors.
F‐Amplitude, left atrial appendage velocity, and thromboembolic risk in nonrheumatic atrial fibrillation
Authors: Blackshear Joseph L. , Safford Robert E. , Pearce Lesly A. ,   On Behalf of the Stroke Prevention in Atrial Fibrillation Investigators
Published: August 2009

AbstractBackground: Reduced left atrial appendage velocity (LAAV) has been identified as a marker for thromboembolism in patients with atrial fibrillation.Hypothesis: It was postulated that electrocardiographic (ECG) F‐wave amplitude would correlate with LAAV, and inversely with the risk of thromboembolism in patients with atrial fibrillation.Methods: In all, 53 patients with nonrheumatic (NRAF) and 7 patients with rheumatic (RAF) atrial fibrillation underwent assessment of maximum LAAV, which was correlated to the maximum ECG F‐wave voltage from lead V1 (Fmax). In 450 NRAF patients on neither aspirin nor warfarin, the relationship between Fmax and thromboembolic risk was assessed over an average follow‐up of 1.3 years.Results: Fmax did not correlate with LAAV (r = 0.2, p = 0.07). Patients with intermittent atrial fibrillation (n = 123) had smaller Fmax amplitude than patients with constant atrial fibrillation (n = 327) (mean 0.73 vs. 0.88 mV−1, p = 0.001). Fmax amplitude was not related to a history of hypertension, systolic blood pressure, duration of NRAF, abnormal transthoracic echocardiographic left ventricular (LV) systolic function or left atrial (LA) diameter. There was a strong trend for increased LV mass being related to smaller Fmax amplitude after adjusting for body surface area (p = 0.06). Fmax amplitude was not correlated with risk of embolic events, including only those events presumed by a panel of case‐blinded neurologists to be cardioembolic.Conclusion: Fmax amplitude in NRAF is smaller in patients with intermittent versus constant AF. It does not correlate with LAAV, LA size, increased LV mass, or systolic dysfunction, hypertension, or risk of embolism. Therefore, Fmax amplitude may not be used as a surrogate for LAAV, or as a measure of thromboembolic risk in NRAF.
Holmium laser‐assisted coronary angioplasty in acute ischemic syndromes
Authors: De Marchena Eduardo , Larrain German , Posada Juan D. , Tang Sherman , Mcghee Vivian , Mallon Stephen 
Published: August 2009

AbstractBackground and hypothesis: Initial studies have shown holmium laser to be effective in ablation of coronary atheromam, and small studies suggest that it may be helpful in ablation of thrombotic stenoses. Therefore, holmium laser‐assisted coronary angioplasty was studied in 85 consecutive patients with acute ischemia syndromes.Methods: Indications for therapy were acute myocardial infarction (MI) in 7 patients (8%), post‐MI ischemic in 32 patients (38%), and crescendo angina pectoris in 46 patients (54%). Coronary morphology characteristics by multivessel angioplasty prognosis group criteria were Type A in 9 (10%), Type B1 in 15 (18%), Type B2 in 44 (52%), Type C in 17 patients (20%).Results: Angiographic evidence of thrombus was seen in 37 (44%) of patients. The laser successfully crossed the total length of the coronary narrowing in 76 patients (89%). Procedure/clinical success was 92% for the total study population, 100% for patients with acute MI, 94% for post‐MI ischemia patients, and 89% for patients with crescendo angina. Lesions with and without thrombus had identical procedure succes rates. Major complication rate was 3.5%, (deaths 0%, Q‐wave MI 0%, and emergent bypass surgery 3.5%). Six‐month angiographic restenosis rate (>50% stenosis) was 45%.Conclusion: Holmium laser‐assisted balloon angioplasty appears promising in the treatment of acute ischemic syndromes and thrombotic coronary lesions.
Prognosis of patients with frequent premature ventricular complexes and nonsustained ventricular tachycardia after coronary artery bypass graft surgery
Authors: Pinto Rodger P. , Romerill David B. , Nasser William K. , Schier John J. , Surawicz Borys 
Published: August 2009

AbstractBackground: Previous studies in small groups of predominantly nongeriatic patients showed that complè ventricular arrhythmias occurring after coronary artery graft (CABG) surgery are of no prognostic significance. The purpose of this study was to compare the prognosis of patients with and without advanced grade ventricular arrhythmias (AGVA) after CABG in a large group of patients. [In this paper, AGVA is used as an abridged definition of frequent premature ventricular complexes (PVCs) and nonsustained ventricular tachycardia (NSVT) which represent advanced grade ventricular arrhythmias.]Methods: Twenty‐four hour ambulatory electrocardiographic (ECG) monitoring was performed 3 days after CABG in 185 consecutive patients with and 185 closely matched control patients without AGVA. Of 185 patients with AGVA, 77 had frequent PVCs, 45 had NSVT, and 63 patients had both. The average age of both groups was 65 ± 9.7 years. Patients were followed for 34 ± 10 months, and in 30 patients ambulatory monitoring was repeated at the end of the follow‐up.Results: Fifteen AGVA and nine control patients died. In each group seven deaths were noncardiac. Six nonsudden and two sudden cardiac deaths (SCD) occurred in the AGVA group at 2‐36 months after CABG and two nonsudden cardiac deaths in the control group at 3 and 35 months after CABG (p = 0.053). Both SCDs occurred 33 months after CABG after new events known to predispose to SCD. In 18 of 30 patients AGVÀ was no longer present when ambulatory ECG monitoring was repeated 36 ± 11 months after CABG.Conclusions: AGVA after CABG was not a marker of an early sudden cardiac death. In 60% of patients not treated with antiarrhythmic drugs, AGVA was no longer present late after operation.
Ionic mechanisms of ischemia‐related ventricular arrhythmias
Authors: Ducceschi Valentino , Di Micco Gianluca , Sarubbi Berardo , Russo Biancamaria , Santangelo Lucio , Iacono Aldo 
Published: August 2009

AbstractThe aim of this review is the utmost simplification of the cellular electrophysiologic background of ischemia‐related arrhythmias. In the acute and subacute phase of myocardial infarction, arrhythmias can be caused by an abnormal impulse generation, abnormal automaticity or triggered activity caused by early or delayed afterdepolarizations (EAD and DAD), or by abnormalities of impulse conduction (i.e., reentry). This paper addresses therapeutic intervention aimed at preventing the depolarization of “pathologic” slow fibers, counteracting the inward calcium (Ca) influx that takes place through the L‐type channels (Ca antagonists), or hyperpolarizing the diastolic membrane action potential, increasing potassium (K) efflux (K‐channel openers) in arrhythmias generated by an abnormal automaticity (ectopic tachycardias or accelerated idioventricular rhythms). If the cause of enhanced impulse generation is related to triggered activity, and since both EAD and DAD are dependent on calcium currents that can appear during a delayed repolarization, the therapeutic options are to shorten the repolarization phase through K‐channel openers or Ca antagonists, or to suppress the inward currents directly responsible for the afterdepolarization with Ca blockers. Magnesium seems to represent a reasonable choice, as it is able to shorten the action potential duration and to function as a Ca antagonist. Abnormalities of impulse conduction (reentry) account for the remainder of arrhythmias that occur in the acute and subacute phase of ischemia and for most dysrhythmias that develop during the chronic phase. Reentrant circuits due to ischemia are usually Na channel‐dependent. Drug choice will depend on the length of the excitable gap: in case of a short gap (ventricular fibrillation, polymorphic ventricular tachycardia, etc.), the refractory period has been identified as the most vulnerable parameter, and therefore a correct therapeutic approach will be based on drugs able to prolong the effective refractory period (K‐channel blockers, such as class III antiarrhythmic drugs); on the other hand, for those arrhythmias characterized by a long excitable gap (most of the monomorphic ventricular tachycardias), the most appropriate therapeutic intervention consists of depressing ventricular excit‐ability and conduction by use of sodium‐channel blockers such as mexiletine and lidocaine. Compared with other class I antiarrhythmic agents, these drugs minimally affect refractoriness and exhibit a use‐dependent effect and a voltage‐dependent action (i.e., more pronounced on the ischemic tissue because of its partial depolarization).
Regional cardiac compression due to a large anaerobic bacterial empyema
Authors: Colleran John A. , Papademetriou Vasilios , Lu David , Fletcher Ross D. , Ballo Michael S. 
Published: August 2009

AbstractCompression of the heart outside the pericardial sac is a rare cause of hemodynamic compromise and cardiac tamponade. We report an atypical case of regional cardiac compression caused by a large loculated anaerobic bacterial empyema.
Malposition of transvenous pacing lead in the left ventricle
Authors: Raghavan Chakravarthy , Cashion W. Richard , Spencer William H. 
Published: August 2009

AbstractTransvenous pacemaker lead malposition in the left ventricle occurs rarely and requires a high index of suspicion for proper diagnosis. The case of a woman with unintentional lead placement in the left ventricle is presented. She had two episodes of transient neurologic deficits, possibly secondary to embolic events, and was started on oral anticoagulants. Chest x‐ray and electrocardiogram (ECG) suggested pacemaker lead malposition and transesophageal echocardiography revealed sinus, venosus atrial septal defect. The lead was shown to cross the atrial septum and the mitral valve to the left ventricle. The malpositioned lead was successfully removed from the left ventricle at the time of surgical repair of the atrial septal defect. The potential value of 12‐lead ECG, chest x‐ray, posteroanterior and lateral views, and echocardiography in the diagnosis of pacemaker lead malposition are discussed and recommendations to avoid this complication at the time of pacemaker implant are outlined.
Wound healing following myocardial infarction
Authors: Weber Karl. T. , Sun Yao , Katwa Laxmansa C. 
Published: August 2009

AbstractA wound‐healing response that eventuates in fibrous tissue formation appears at the site of myocardial infarction (MI) in the affected ventricle. Fibrosis can likewise appear remote to the MI and cause an extensive structural remodeling of the myocardium of infarcted and noninfarcted ventricles. Substances involved in promoting healing at and remote to MI are of considerable interest and an important clinical issue, given that the healing response is subject to pharmacologic intervention. Angiotensin‐converting enzyme (ACE) is expressed by wound‐healing fibroblast‐like cells; it likely serves to regulate local concentrations of angiotensin II and bradykinin involved in healing and matrix remodeling. Wound healing following MI and its regulation are addressed in this review.
Evaluation of heart failure patients: Objective parameters to assess functional capacity
Authors: Mills Roger M. , Haught W. Herbert 
Published: August 2009

AbstractMeasures of disease severity used in the evaluation of patients with heart failure include survival data, the New York Heart Association classification, ejection fraction, functional assessments, exercise protocols, rest and exercise hemodynamic data, and biochemical parameters including catecholamine levels and serum sodium. Clinicians must integrate these multiple variables into an overall assessment. An overview of the clinical application of these techniques in the evaluation and treatment of patients with heart failure is presented.
Effects of intracoronary carbon dioxide on left ventricular function in swine
Authors: Lambert Charles R. , Bikkina Mahesh , Arcement Brian K. , De Marchena Eduardo J. 
Published: August 2009

AbstractBackground and hypothesis: Carbon dioxide is currently used as an arterial and venous contrast agent; however, little is known of its effects on left ventricular function. This study was undertaken to investigate those effects.Methods: Ascending doses of 5, 10, and 20 ml of carbon dioxide were administered into the left main coronary artery of domestic swine with and without a continuous infusion of intravenous nitroglycerin (50 μg/min).Results: Carbon dioxide had an immediate and profound depressant effect on both systolic and diastolic left ventricular function associated with ischemic electrocardiographic changes. Compared with controls (% change), ascending doses of carbon dioxide decreased systolic pressure by −35 ± 7, −48 ± 8, and −53 ± 4 in the absence of nitroglycerin, and by −32 ± 9, −50 ± 9, and −60 ± 9 in the presence of nitroglycerin. Peak +dP/dt decreased by −54 ± 7, −61 ± 11, and −64 ± 3 in the absence of nitroglycerin, and by −36 ± 13, −55 ± 11, and −65 ± 11 in the presence of nitroglycerin. Minimum ‐dP/dt increased by 65 ± 8, 71 ± 8, and 77 ± 3 in the absence of nitroglycerin, and by 63 ± 7, 71 ± 8, and 78 ± 7 in the presence of nitroglycerin. No significant changes in heart rate were observed; however, widespread ST‐segment elevation was observed in all animals. Coronary angiography following carbon dioxide injection revealed a marked decrease in coronary flow velocity until the gas was cleared from the microcirculation. This was also documented by direct measurement of flow velocity using a Doppler catheter in an additional animal. Left ventriculography demonstrated immediate global dilation and depression of systolic function.Conclusions: In the swine model, relatively small doses of intracoronary carbon dioxide cause profound yet reversible global left ventricular dysfunction which appears to be ischemic in origin.