Fifty-one patients (mean age 51.6 +/- 7.1 years) with angiographically proven coronary artery disease (CAD) entered the study. In 26 patients (Group I), trimetazidine treatment started twenty-four hours after percutaneous transluminal coronary angioplasty (PTCA). Another 25 patients (Group II) without trimetazidine treatment were kept as controls. The groups were comparable by age, gender, risk factors of CAD, coronary anatomy, left ventricular performance, and heart rate variability indices at baseline state. Power spectral analysis of heart rate variability and two-dimensional and Doppler echocardiographic examinations were performed before PTCA, and twenty-four hours, ten days, thirty days, and three months after PTCA. A statistically significant improvement of left ventricular systolic performance (P<0.001), augmentation of the parasympathetic band of heart rate variability (P<0.001), and decline of P1/P2 ratio (P<0.01) were evident in patients treated with trimetazidine, while no apparent changes were observed in controls. The intergroup analysis also showed marked difference between groups as recorded on the day 30 and month 3 of observation (P<0.001). During follow-up period recurrences of angina pectoris and ischemia were registered in Group II, while no evidence of ischemia was discerned in Group I patients. In conclusion, trimetazidine modulates the autonomic control of heart rate, ie, reduces sympathetic overactivity and augments vagal influences, improves left ventricular contractility, and diminishes the clinical manifestations of ischemia in patients with CAD after PTCA.