bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conventional Electrocardiogram in Arrhythmogenic Right Ventricular Dysplasia‐Cardiomyopathy and Idiopathic Right Ventricular Outflow Tract Tachycardia
Authors: Peters Stefan , Weber Bettina , Reil Gert‐Hinrich 
Published: October 2006

Objective: Arrhythmogenic right ventricular dysplasia up to now is a rare cardiomyopathic entity with certain difficulties in clinical definition of diagnostic criteria. In 42 patients with major and minor criteria of arrhythmogenic right ventricular dysplasia and 25 patients with idiopathic ventricular arrhythmia, the role of conventional ECG in the diagnosis of arrhythmogenic right ventricular dysplasia was reevaluated.Methods: In standard 12‐lead ECG, QRS duration was measured in limb lead D1, and in V1‐V6. A ratio of the sum of right (V2+ V3) and left (V4+ V5) was calculated. T wave inversions, Epsilon wave, and mechanisms of advancing right bundle branch block were analyzed.Results: In 39 out of 42 patients (93%) with the diagnosis of arrhythmogenic right ventricular dysplasia, a ratio of right and left precordial QRS duration of >1.2, a maximum right precordial QRS duration of > 100 ms in 10 cases (26%) and >110 ms in 29 cases (74%) could be found. Incomplete right bundle branch block with right precordial T inversions was found in one case. The ECG in two patients revealed a precordial R/S transition in V1 or V2; in all other cases, R/S transition was localized in V3 or V4. R peak time was normal (< 0.04 s) in all cases, a “notching” or “slurring” of the S wave was striking in 16 cases. T wave inversions were found in 27 cases and definite Epsilon wave in only one case. Although incomplete right bundle branch block and certain preforms could also be disclosed in four patients with idiopathic right ventricular outflow tract (RVOT) tachycardia, localized right precordial QRS prolongation could be excluded in all but one of these cases. Localized right precordial QRS duration prolongation in one case was probably due to a rotation of the heart with a precordial R/S transition between V1 and V2.Conclusion: Localized right precordial QRS prolongation in a normal precordial R/S transition: (a) seems to be the most important aspect of arrhythmogenic right ventricular dysplasia at conventional ECG, with a sensitivity of 93% and a specificity of 96% in order to distinguish idiopathic RVOT tachycardia; (b) can appear with (64%) or without (36%) secondary T wave inversions; and (c) is due to a “parietal” block sparing the specialized conducting system.
Deletion Polymorphism of the Angiotensin I‐Converting Enzyme Gene Associates with Increased Risk for Late Potentials in Patients with Myocardial Infarction
Authors: Nakai Kenji , Chiba Naoki , Shobuzawa Minoru , Musha Takehiko , Shiroto Takahiro , Hosokawa Shunichi , Kamata Junya , Suzuki Tomomi , Aoki Hidehiko , Saiki Seiichi , Hiramori Katsuhiko 
Published: October 2006

Background: The pathogenesis of the occurrence of late potentials (LP) has not been fully elucidated. Deletion polymorphism in the Angiotensin I‐converting enzyme (ACE) gene may relate the myocarclial remodeling after the myocardial infarction (Ml). The purpose of this study was to evaluate the significance of ACE gene polymorphism for the occurrence of LPs after Ml.Methods: A 287 base pair (bp) insertion/deletion polymorphism in intron 16 of the ACE gene was determined by polymerase chain reaction and LPs were also examined by signal‐averaged EGC in 136 patients with Ml. Polymorphism of the ACE gene was characterized by three genotypes: II, ID, and DD. Signal‐averaged ECG were recorded using X, Y, Z leads and LP were defined by time‐domain analysis as low amplitude potentials exceeding 20 ms after the QRS‐end and filtered QRS >115 ms.Results: Positive LPs were noted in 40 of 136 patients with Ml. No differences could be detected between patients with LP‐positive and LP‐negative for the location of Ml, the success rate of reperfusion therapy, and left ventricular end‐diastolic volume (126 ± 40 vs 113 ± 43 mL/m2). In patients with LP‐positive compared with those in LP‐negative, filtered QRS was significantly higher (135 ± 8 vs 107 ± 8 ms), left ventricular ejection fraction was lower (47 ± 12 vs 54%± 11 %), and peak was higher (3602 ± 2928 vs 2614 ± 2360 IU/L). The frequency of ACE/DD genotype was associated with patients with LP‐positive (18 of DD, 18 of ID, and 4 of II for patients with LP‐positive, while 25 of DD, 42 of ID, and 29 of II for patients with LP‐negative). In the study population, the ACE / DD genotype was associated with patients with LP‐positive when compared with the ACE ID & II genotype (x2= 4.7, P = 0.03).Conclusion: ACE/DD genotype of the ACE gene may be associated with the occurrence of LP after Ml.
The Clinical Significance of Somatic Pain Tolerance in Patients with Coronary Artery Disease
Authors: Narins Craig R. , Zareba Wojciech , Moss Arthur J. , Brown Mary W. , Case Robert B. , Case Nan , Goldstein Robert E. 
Published: October 2006

MethodsTwo hundred seventy‐one patients with a recent acute coronary event underwent pain tolerance testing using the tourniquet test. Baseline ambulatory and exercise electrocardiography, and stress thallium scintigraphy were performed, and patients were followed prospectively for a mean of 33 ± 8 months for the occurrence of unstable angina, nonfatal myocardial infarction (Ml), or cardiac death.ResultsPatients with lower tolerance to somatic pain were significantly older (P = 0.001), had more clinical angina (P = 0.04), and on multivariate analysis had poorer exercise tolerance (P = 0.002) than those with higher pain tolerance. Low and high pain tolerance patients demonstrated similar degrees of myocardial ischemia on noninvasive testing and had similar cardiac event rates (death, nonfatal Ml, or unstable angina) during the follow‐up period.ConclusionsDespite demonstrating a similar frequency of myocardial ischemia and similar prognosis as patients with high pain tolerance, individuals with low pain tolerance were more likely to experience clinical symptoms and functional impairment, providing evidence that individual differences in somatic pain tolerance influence the symptomatic expression of coronary disease.
Sequential Alterations in Myocardial Lactate Metabolism, S‐T Segments, and Left Ventricular Function During Angina Induced by Atrial Pacing
Authors: PARKER JOHN O. , CHIONG MIGUEL A. , WEST ROXFOY O. , CASE ROBERT B. 
Published: October 2006

SUMMARYMyocardial lactate metabolism was monitored before, during, and after a period of atrial pacing with a continuous automated sampling technic. The electrocardiogram was recorded, and left ventricular function was evaluated by relating left ventricular end‐diastolic pressure to left ventricular stroke work. Seventeen of 21 patients with coronary artery disease experienced angina during pacing, and 13 of these showed lactate production by the myocardium during angina. The abnormalities in lactate metabolism developed early in the pacing period, along with S‐T segment depression and impairment of left ventricular function, all of which usually occurred before the onset of pain. In the patients with angina, the mean lactate extraction was 14.1% during the control period and —15.1% during the pacing period. Abnormalities in myocardial lactate metabolism have been demonstrated with greater regularity during pacing‐induced angina than during angina precipitated by exercise or isoproterenol. This investigation has demonstrated the sequences of changes in lactate metabolism during and after a period of angina and their relation to electrocardiographic and hemodynamic events.
Comparison of the Proarrhythmic Effect of GLG‐V‐13, a Novel Class III Antiarrhythmic Compound, in Two Rabbit Models of Torsades de Pointes Ventricular Tachycardia
Authors: Fazekas Tamás , Szilvassy Zoltan , Carlsson Leif , Berlin K. Darrell , Scherlag Benjamin J. , Patterson Eugene , Lazzara Ralph 
Published: October 2006

Objective: The proarrhythmic potential of a new IKr‐blocking Class III antiarrhythmic agent, GLG‐V‐13 was studied and compared in two rabbit models of torsades de pointes (TdP) ventricular tachycardia (TdP).Methods: Chloralose‐anesthetized rabbits (n = 8) were given a concomitant infusion of GLG‐V13 (84 nmol/kg per min) and the α1‐agonist methoxamine (70 nmol/kg per min); in another set of experiments, GLG‐V‐13 was administered solely into the ear vein of electrode catheter instrumented conscious rabbits (n = 6). The doses of GLG‐V‐13, to produce maximum prolongation of the QTUc interval or the right ventricular effective refractory period (VERP), and that inducing ventricular ectopic beats (EBs) and TdP, respectively, were determined.Results: In anesthetized rabbits, GLG‐V‐13 increased QTUc from 125 ± 3 to 161 ± 6 ms after a cumulative dose of 0.84 μmol/kg (P < 0.001) and caused EBs at a mean cumulative dose of 3.9 ± 1.1 μmol/kg. In five of the rabbits, the EBs turned into TdP at a dose of 5.2 ± 3.2 μmol/kg. In conscious rabbits, maximum prolongation of the VERP (27%± 4.3%; P < 0.01) by GLG‐V‐13 was seen at a dose of 1.2 ± 0.54 μmol/kg, whereas EBs and TdP were induced after 6.3 ± 1.4 (6/6) and 8.1 ± 1.4 μmol/kg (6/6), respectively.Conclusion: (1) The dose‐dependent “torsadogenic” potential of IKr‐blockers can be evaluated in conscious rabbits without concomitant methoxamine administration; (2) in the conscious state, the EB‐ and TdP‐inducing dose of GLG‐V‐13 is about 50% higher than in the chloralose‐anesthetized animal; and (3) irrespective of the chemical nature of the compound applied, blockade of the cardiac IKr potassium channel is associated with proarrhythmic effect.
Gender Specificities in Risk Stratification After Myocardial Infarction
Authors: Copie Xavier , Hnatkova Katerina , Fei Lü , Staunton Anne , Camm A. John , Malik Marek 
Published: October 2006

Objective: Although gender specificities of various risk factors have been well documented, risk stratification after myocardial infarction has never been compared in women and men.Methods: The power of left ventricular ejection fraction, heart rate variability, and mean RR interval computed from 24‐hour Holter recordings, was compared in women and men for the prediction of cardiac mortality after an acute myocardial infarction. The study population consisted of 456 patients (108 women, 348 men) aged 50–75 years.Results: During a follow‐up of 3 years, there were 41 cardiac deaths (13 women vs 28 men, P = NS). The positive predictive accuracy of left ventricular ejection fraction, heart rate variability, and mean RR interval at all sensitivity levels was higher in women than in men. For a 40% sensitivity, positive predictive accuracy of left ventricular ejection fraction was 46% in women and 16% in men (P < 0.05), positive predictive accuracy of mean RR interval was 90% in women and 28% in men (P < 0.05), and positive predictive accuracy of heart rate variability was 61% in women and 43% in men (P = NS). Mean RR interval had the highest positive predictive accuracy for cardiac mortality in women, but its superiority over heart rate variability was not statistically significant. In men, heart rate variability was the strongest predictor of mortality that was significantly more powerful than mean RR interval and left ventricular ejection fraction (P < 0.05).Conclusion: Increased 24‐hour mean heart rate is the strongest predictor of cardiac mortality in women in whom it performs significantly better than in men. While in men, heart rate variability is a significantly better predictor of postinfarction cardiac mortality than 24‐hour mean heart rate, this is not the case in women.
Hemodynamic Determinants of Silent ST Segment Depression in Patients with Hypertrophic Cardiomyopathy Treated with Verapamil
Authors: Dimitrow Paweł Petkow , Surdacki Andrzej , Kakol Janusz , Jasiriski Tomasz , Dubiel Jacek Stefan , Janicki Kazimierz 
Published: October 2006

Objective: The aim of the study was to establish mechanisms of ischemic type, painless ST segment depression in nine patients with nonobstructive hypertrophic cardiomyopathy (HC) treated effectively by verapamil.Methods: Simultaneous 24‐hour Holter and blood pressure monitoring (measurements every 15 minutes) was performed to determine approximate indices of myocardial oxygen demand (double product), myocardial oxygen supply (diastolic blood pressure), and ST segment level during each minute when blood pressure measurements were obtained. According to ST segment level, all recordings were divided into four subgroups (one without and three with gradually increasing magnitude of ST segment depression) in which average double product and diastolic blood pressure were calculated.Results: Increasing ST segment depression coincided with gradual rises in double product indicating increasing myocardial oxygen consumption. Diastolic blood pressure was low in the group without ST segment deviation whereas it was significantly higher only in groups with ST segment depression of more than 2 mm.Conclusion: Verapamil‐induced, excessive fail of diastolic blood pressure was not associated with exacerbating ST segment depression. On the other hand, occasionally verapamil insufficiently prevented increases of double product, which coincided with the prescence of painless ST segment depression episodes.
Can Dispersion of the QT Interval Identify Inducible Monomorphic Versus Polymorphic Ventricular Tachycardia?
Authors: Clay Anthony , Dreifus Leonard S. , Zaim Sina , Kutalek Steven P. 
Published: October 2006

BackgroundDispersion of QT interval has been utilized to stratify patients who may be at risk for lethal ventricular arrhythmias. This study attempted to evaluate the value of QT dispersion in patients undergoing electrophysiological studies (EPSs) to predict inducible monomorphic ventricular tachycardia (MVT) or polymorphic ventricular tachycardia or ventricular fibrillation (PMVT/VF).MethodsEPSs were performed on 33 patients with a history of symptomatic MVT and PMVT/VF. Seventeen patients were induced by EPS to MVT and 13 patients to PMVT/VF; three other patients could not be induced. The QT limb (QTL, QTCL), precordial (QTP, QTcP) and dispersion measurements, and limb (QTLd, QTcLd, JTLd) and precordial (QTpd, QTcPd, JTPd), were analyzed by two independent observers. Except for the QTP which appeared longer in patients with PMVT/VF than in patients with MVT (468 ± 124 vs 410 ± 41.8 ms, P < 0.05), there was no statistical difference between the QT, QTc, QTd, JTd and induced MVT vs PMVT/VF.ConclusionOur data suggest that QT dispersion considering limb leads, precordial leads, or a combination of all leads did not predict inducible MVT vs PMVT/VF in patients presenting with serious index ventricular arrhythmias. A.N.E. 1998; 3(1):20–24
The Long QT Syndrome
Authors: Schwartz Peter J. , Priori Silvia G. 
Published: October 2006

Major progress has taken place, and at a very rapid pace, in the understanding of the congenital long QT syndrome (LQTS). This has been the direct consequence of the identification of several of the genes responsible for LQTS and of the studies that have followed, at both basic and clinical levels. A key issue is represented by the fact that all LQTS genes identified so far encode for ionic channels involved in the control of repolarization. The expression studies of the mutated genes have allowed identification of the specific electrophysiologic consequences of the specific mutations and have demonstrated alterations in the NA+ and in K+ currents sufficient to explain the prolongation of action potential duration and, hence, of the QT interval.Ongoing studies in the selected LQTS patients, for whom the specific mutations are known, are allowing a unique understanding of the complex genotype‐phenotype correlation. These studies indicate the existence of what appear to be gene‐specific patterns in many clinically important features such as the response to therapeutic interventions, the response to increases in heart rate, and in the factors that precipitate the life‐threatening arrhythmias typical of this intriguing disease.
The Association Between Residual Myocardial Ischemia and Heart Rate Variability Early After Acute Myocardial Infarction
Authors: Quintana Miguel , Lindvall Kaj , Storck Niklas 
Published: October 2006

BackgroundResidual myocardial ischemia and decreased heart rate variability (HRV) are common findings during the acute phase of acute myocardial infarction. Both signs have been associated with a poor prognosis. The present study investigated the association between residual myocardial ischemia and HRV in the early phase after AMI.Patients and MethodsSeventy‐four patients were monitored with ambulatory electrocardiography during 23 ± 1 hours, 4 ± 1 days after AMI. In addition, 24 healthy individuals (controls) with similar age and gender were also monitored. HRV was computed in time and frequency domains. Residual myocardial ischemia was defined as the presence of ST‐segment depression during ambulatory electrocardiography, defined as a 0.1 mV horizontal or downsloping ST‐segment deviation from the reference level, elapsing 1 minute or longer, measured 80 ms after the J point.ResultsResidual myocardial ischemia was found in 22 (30%) patients. Some time‐domain and all frequency‐domain measures of HRV were lower in patients showing residual myocardial ischemia compared with those without residual myocardial ischemia. All time‐ and frequency‐domain measures of HRV were higher in controls compared with patients with residual myocardial ischemia. Only SDNN and low frequency band values were lower in patients without residual myocardial ischemia compared with healthy controls. Both residual myocardial ischemia and a decreased HRV were associated with poor in‐hospital outcome.ConclusionsPatients showing residual myocardial ischemia during ambulatory electrocardiography performed early after AMI had lower values of HRV compared with those without residual myocardial ischemia. The causality between these findings are not still defined and deserve further research.
Normal Dispersion of Ventricular Repolarization in Patients with Kawasaki Disease Who Develop Coronary Artery Abnormalities
Authors: Berul Charles I. , Hill Sharon L. , Fulton David R. 
Published: October 2006

BackgroundKawasaki disease (KD) is complicated by coronary artery abnormalities (CAA) in 3%‐25% of patients, depending on acute therapy. ECG markers of ventricular vulnerability such as QT and JT dispersion, SAECG, and ambulatory monitoring have been shown to have predictive value in disparate diseases such as long QT syndrome, postmyocardial infarction, and atherosclerotic coronary artery disease. The aim of this study was to evaluate the association between QT and JT dispersion and the occurrence of CAA in KD.MethodsOver the past 15 years, we evaluated 814 children with acute KD, of which 24 (3%) developed significant CAA (aneurysms, stenoses). An additional 40 children (5%) developed milder CAA (4–5 mm dilation). Multivariate analysis was used to compare QTc, JTc, and dispersion in the 24 patients who developed significant CAA with three other groups: 40 patients with mild CAA, 750 KD patients without evidence of CAA, and 1000 normal control children. A small prospective study included additional noninvasive ECG markers using ambulatory (Holter) monitoring and SAECG.ResultsThere were no significant differences in any ECG measures of ventricular repolarization among any of the three KD groups and the normal control pediatric ECGs.ConclusionsIncreased dispersion of ventricular repolarization is not associated with coronary‐artery abnormalities in KD.
Spontaneous Variability of Ventricular Ectopic Activity in Patients with Sustained Ventricular Tachycardia and in Survivors of Cardiac Arrest
Authors: Anastasiou‐Nana Maria I. , Karagounis Labros A. , Anderson Jeffrey L. , Mason Jay W. 
Published: October 2006

Background: Spontaneous variability of ventricular arrhythmia has been described in patients with chronic stable ventricular arrhythmias and in patients with chronic heart failure. However, no data are available on spontaneous variability in patients with sustained ventricular tachyarrhythmias. Thus, the present study was designed to prospectively determine the extent of spontaneous variability of ventricular arrhythmia in patients with sustained ventricular tachyarrhythmias and in survivors of cardiac arrest.Methods: Ventricular arrhythmia variability was determined in 470 patients (413 men, 57 women), age (mean ± SD) 64.6 ± 9.5 years with documented ventricular tachycardia (VT), cardiac arrest, or syncope who were prospectively enrolled in a randomized trial of the comparison of electrophysiological testing with Holter monitoring to predict antiarrhythmic drug efficacy. Coronary artery disease was present in 398 (85%) patients, and the mean left ventricular ejection fraction was 0.32 ± 0.13. They underwent two 24‐hour ambulatory recordings separated by 1 day. Spontaneous variability was determined for total premature ventricular complexes (PVCs), pairs, and VT events.Results: Arithmetic mean of hourly total PVCs on day 1 was 315 ± 425. The 95% confidence limit of spontaneous reduction in total PVC count was 71%. Corresponding values for pairs, VT events of 3–15 beats, < 15 beats, or < 15 seconds were 72%, 80%, 94%, and 95%, respectively. The percentage increases in total PVCs, pairs, and VT events 3–15 beats, < 15 beats, and < 15 seconds were 243%, 259%, 397%, 1553%, and 1756%, respectively. The percentage reduction required to show a true drug effect was 63% for patients with an ejection fraction > 0.32 and 76% for those with an ejection fraction ltm 0.32 (P = 0.024). Patients who presented with unmonitored syncope showed less spontaneous variability than either patients with documented, sustained VT or cardiac arrest.Conclusions: Marked spontaneous variability of ventricular arrhythmias is observed in patients with sustained ventricular tachyarrhythmias. Variability is affected by the degree of left ventricular dysfunction. The lowest variability was observed in patients presenting with unmonitored syncope. Thus, large changes in arrhythmia frequency must be observed in this population, as in others, to be ascribed to drug effect.