BACKGROUND The genesis of the electrocardiographic T wave is incompletely understood and subject to controversy. We have correlated the ventricular repolarization sequence with simultaneously recorded T waves. METHODS AND RESULTS Nine pig hearts were Langendorff-perfused (atrial pacing, cycle length 650 ms). Local activation and repolarization times were derived from unipolar electrograms sam...

The reason for sex differences in arrhythmic risk remains unclear. Heterogeneity of ventricular repolarization is directly linked to arrhythmogenesis; thus we investigated repolarization homogeneity and its circadian pattern in men and women. During 24-h Holter recordings in 60 healthy subjects (27 males), a 12-lead electrocardiogram (ECG) was obtained every 30 s. RR and QT intervals, and, afte...

BACKGROUND Altered cardiac repolarization and increased dispersion of repolarization have been identified as risk factors for sudden cardiac death (SCD). The prevalence of and the mechanisms contributing to altered cardiac repolarization are currently unknown in COPD. METHODS In 91 COPD patients, 32 controls matched for age, cardiovascular risk and medication, and 41 healthy subjects, measure...

BACKGROUND Proarrhythmic effects of cardiac resynchronization therapy (CRT) as a result of increased transmural dispersion of repolarization (TDR) induced by left ventricular (LV) epicardial pacing in a subset of vulnerable patients have been reported. The possibility of identifying these patients by ECG repolarization indices has been suggested. OBJECTIVES The purpose of this study was to te...

Recent epidemiological studies documented that early repolarization may be associated with increased risk of serious cardiac events, including cardiac death. Little is known about the prognostic significance of this pattern in low risk surgical patients. This retrospective study included 3028 patients over 18 years of age and with ASA class I and II risk, undergoing noncardiac elective surgery....

Abnormally long and short QT intervals have been shown to be associated with an increased risk for life-threatening ventricular arrhythmias and sudden cardiac death. In recent years, various methods for QT-interval measurement have been developed, including individual-based corrections for repolarization duration, quantitative assessment of repolarization morphology, correction for repolarizati...

Background: Cellular repolarization abnormalities occur unpredictably due to disease and drug effects, and can occur even in cardiomyocytes that exhibit normal action potentials (AP) under control conditions. Variability in ion channel densities may explain differences in this susceptibility to repolarization abnormalities. Here, we quantify the importance of key ionic mechanisms determining re...

BACKGROUND Cardiac memory refers to the observation that altered cardiac electrical activation results in repolarization changes that persist after the restoration of a normal activation pattern. Animal studies, however, have yielded disparate conclusions, both regarding the spatial pattern of repolarization changes in cardiac memory and the underlying mechanisms. The present study was undertak...

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INTRODUCTION No data regarding the prevalence of the Brugada-type electrocardiogram (ECG) pattern and the early ventricular repolarization pattern (ERP) in the North African population were available. The aims of this study were to determine the frequency of Brugada-type ECG pattern and ERP in Tunisia and to evaluate ECG descriptors of ventricular repolarization in a population of athletes. M...