Prognostic significance of duration and dispersion of interval QT as well as relationship of these parameters to other clinical and instrumental signs were studied in 220 survivors of acute myocardial infarction (MI). These patients were examined on days 10-14 of MI and then followed for 12-36 months. Values of corrected QT (QTc) increased with increase of degree of severity of heart failure and derangements of left ventricular function, intensity of ventricular disturbances of rhythm. QT dispersion depended on left ventricular contractile function and rose in anterior localization of MI and non-Q MI. Dependence was observed between QTc duration and mortality of patients after MI, both total and cardiovascular including sudden. At multifactorial analysis QTc>440 ms appeared to be independent predictor of risk of total and cardiac mortality in patients with anterior non-Q MI. QT dispersion did not possess sufficient informative power for prognostication of outcomes.