Fifty-four patients with acute myocardial infarction were treated with thrombolytic therapy (27 with rTPA and 27 with streptokinase). In all the subjects CK was monitored (every 3 hours) and ergometric test, echocardiogram, and 24 hours holter ecg were performed in the pre-discharge period. In 22 of the patients, coronary angiography was also performed. No differences were shown between the two groups of patients as regards CK values and ejection fraction. Repetitive ventricular premature beats were registered without difference between the two groups (23% in patients treated with SK and 18% in the patients treated with rTPA). No bleeding events were shown in the patients treated with rTPA without calciparin. On the other hand no difference there was between patients treated with rTPA + calciparin and patients treated with SK with or without calciparin.