Aims: The most widely accepted marker for stratifying the risk of sudden cardiac death (SCD) in post myocardial infarction patients is a depressed left ventricular function. Left ventricular ejection fractions (EF) of 35% or less increase the risk of sudden death but values between 35 and 40% raise concern. The underlying pathophysiological mechanism is sustained ventricular tachycardia or fibrillation, both associated with increased cardiac repolarization variability.
View Article and Find Full Text PDFUnlabelled: The QT variability index (QTVI) indicates temporal dispersion in myocardial repolarization, and a high QTVI is associated with a propensity for sudden death from malignant ventricular arrhythmias in subjects at high risk. In this study, the authors assessed the effects of free breathing, controlled breathing, and sympathetic stress (tilt) on the QTVI in patients with chronic heart failure (CHF) and healthy control subjects. The authors also examined the influence of age on the same variables.
View Article and Find Full Text PDFBackground: Several studies have shown that cardiac-resynchronization therapy (CRT) improves haemodynamic function, cardiac symptoms, and heart rate variability (HRV) and reduces the risk of mortality and sudden death in subjects with chronic heart failure (CHF). In subjects with CHF, power spectral values for the low-frequency (LF) component of RR variability < or =13 ms2, are associated with an increased risk of sudden death.
Aims And Methods: To assess whether spectral indexes obtained by power spectral analysis of HRV and systolic blood pressure (SBP) variability could predict malignant ventricular arrhythmias in patients with severe CHF treated with an implantable cardioverter-defibrillator (ICD) alone or with ICD+CRT.