Heart rate variability as a predictor of sudden cardiac death.

Different noninvasive approaches have been developed for risk stratification of patients with myocardial infarction and heart failure with aim to select patients at high risk of sudden cardiac death who might mostly benefit from preventive therapy. Reduced heart rate variability (HRV) was a strong predictor of mortality in myocardial infarction and heart failure in early studies. However, in the era of modern treatment strategies the prognostic significance of HRV indices has been challenged. We thought to review the role of conventional, nonlinear and novel spectral indices of HRV in prediction of sudden cardiac death in patients with myocardial infraction and heart failure.