A total of 283 patients with chronic ischemic and noncoronary heart diseases were investigated. It was established that decreased heart rate variability was associated with process of myocardial remodeling leading
to dilatation and volume overload of cardiac cavities and decreased myocardial contractility with development of heart failure. Decreased heart rate variability was not directly associated with fatal ventricular arrhythmias and was accompanied with higher total mortality predominantly due to advanced heart failure. The data obtained on a low prognostic value of heart rate variability with regard to fatal ventricular arrhythmias and sudden arrhythmic death may reflect the predominance of patients with severe manifestations of heart failure among the investigated. QT interval dispersion was associated with processes of myocardial remodeling leading to heart dilatation, volume overload heart and a decreased myocardial contractility with development of clinical manifestations of heart failure.