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BACKGROUND The goal of the present study was to determine the predictive value of beat-to-beat QT variability in heart failure patients across the continuum of left ventricular dysfunction. METHODS AND RESULTS Beat-to-beat QT variability index (QTVI), log-transformed heart rate variance, normalized QT variance, and coherence between heart rate variability(More)
BACKGROUND The clinical importance of the J-point elevation on electrocardiogram is controversial. OBJECTIVE To study intracardiac J-point amplitude before ventricular arrhythmia. METHODS Baseline 12-lead electrocardiogram and far-field right ventricular intracardiac implantable cardioverter-defibrillator electrograms were recorded at rest in 494(More)
BACKGROUND Methodological difficulties associated with QT measurements prompt the search for new electrocardiographic markers of repolarization heterogeneity. OBJECTIVE We hypothesized that beat-to-beat 3-dimensional vectorcardiogram variability predicts ventricular arrhythmia (VA) in patients with structural heart disease, left ventricular systolic(More)
BACKGROUND Recently we showed the predictive value of sum absolute QRST integral (SAI QRST) and repolarization lability for risk stratification of sudden cardiac death (SCD) in heart failure patients. The goal of this study was to compare SAI QRST and metrics of depolarization and repolarization variability in healthy men and women. METHODS Orthogonal(More)
INTRODUCTION From experiments, we know that the heterogeneity of action potential duration and morphology is an important mechanism of ventricular tachyarrhythmia. Electrocardiogram (ECG) markers of repolarization lability are known; however, lability of depolarization has not been systematically studied. We propose a novel method for the assessment of(More)
BACKGROUND Increased repolarization lability is known to be associated with the risk of ventricular tachycardia (VT)/ventricular fibrillation (VF). Premature ventricular contractions (PVCs) are excluded from the analysis of QT variability. However, QT dynamics after PVCs is poorly understood. METHODS We analyzed data of 33 patients with structural heart(More)
BACKGROUND Antiarrhythmic and proarrhythmic effects of cardiac resynchronization therapy (CRT) remain controversial. We hypothesized that reverse electrical remodeling (RER) with CRT is associated with reduced frequency of ventricular tachyarrhythmias (VTs). METHODS The width of native and paced QRS was measured in lead II electrocardiogram before and 13(More)
BACKGROUND Post-myocardial infarction (MI) structural remodeling is characterized by left ventricular dilatation, fibrosis, and hypertrophy of the non-infarcted myocardium. OBJECTIVE The goal of our study was to quantify post-MI electrical remodeling by measuring the sum absolute QRST integral (SAI QRST). We hypothesized that adverse electrical remodeling(More)
BACKGROUND Despite advances in prevention and treatment of cardiovascular disease, sudden cardiac death (SCD) remains a clinical challenge. Risk stratification in the general population is needed. METHODS AND RESULTS Beat-to-beat spatiotemporal variability in the T vector was measured as the mean angle between consecutive T-wave vectors (mean TT' angle)(More)