36 patients with macrofocal myocardial infarction (MI) underwent systemic thrombolytic therapy with avelysin (500,000-750,000 U) within the disease first 6 hours. By the results of the treatment 2 groups were identified: patients with thrombolysis and myocardial reperfusion (n = 20), patients free of reperfusion manifestations (n = 16). The patients were examined in hospital and outside 10 months after MI development: myocardial contractility and hemodynamics were assessed at echocardiography and radiocardiography, exercise tolerance, coronary and myocardial cardiac reserves using bicycle ergometry. Better exercise tolerance and myocardial contractility were shown both in hospital and in follow-up by patients with myocardial reperfusion. According to the follow-up findings, myocardial contractility was such the same as that on postinfarction week 4, exercise tolerance was much higher than at the first examination. Thus, myocardial reperfusion affects positively the parameters studied in MI patients.