200 patients aged 49 +/- 8 with coronary artery disease underwent selective coronarography, left ventriculography as well as performed every year laboratory, polycardiography, ECG exercise test, 24-hour ECG Holter monitoring and X-ray chest examinations. Mean follow-up period was 34 +/- 10 months. For QT-QS2 index monitoring patients were divided into two groups: I--with abnormal index QT greater than QS2 (61-30%) and II--with the normal one QT less than QS2 (139-70%). Lown's classification was applied for ventricular premature beats assessment. Left ventricular contractility was estimated in hemodynamic examination. 28 patients died due to cardiac reasons during follow-up (14%). Among 19 suddenly died patients (9.5%) 7 had a normal and 12 an abnormal QT-QS2 index. Sudden mortality rate was 5% in the normal QT less than or equal to QS2 subgroup, and 20% in the abnormal QT greater than QS2 one. These differences are statistically significant.