Thrombolytic therapy for acute myocardial infarction is aimed at restoration of coronary blood flow in a vessel occluded by thrombotic material. Coronary angiography is the ''gold standard'' for verification of infarct vessel patency after thrombolytic therapy, but due to irs impossible routine use, daily practice has imposed the need of other, noninvasive clinical indicators. Early occurrence of peak creatine kinase (peak CPK less than or equal to 12 h), reduction in ST-segment elevation by greater than or equal to 50%, to normal level or steady state achieveInelzt within less than or equal to 3 h, and early occurrence (less than or equal to 4 h) of most frequent reperfusion arrhythmias, slow ventricular tachycardia (SVT) were monitored in 50 patients with acute infarction on thrombolytic therapy. Coronary angiography was performed in 20 patients during hospitalization. Comparison of the three reperfusion parameters between the group of patients with coronary angiography (N=20) and patient group as a whole (N=50) showed peak CPK less than or equal to 12 h in 75% vs. 74%, ST-segment reduction by greater than or equal to 50% within less than or equal to 3 h in 65% vs. 68%, and early occurrence of SVT within less than or equal to 4 h in 75% vs. 72% of the patients, respectively (p=NS). Concerning sensitivity, specificity and predictive value of individual markers pointing to coronary artery patency, the following results were obtained: for CPK less than or equal to 12 h in, the angiography group, 75%, 80% and 94%, and in the whole group 74%, 85% and 94% (p=NS); for ST-segment reduction by greater than or equal to 50% within less than or equal to 3 h, 65%, 85% and 94% in. the alzgiography group, and 68%, 87% and 94% in. the group as a whole; and for early occurrence (less than or equal to 4 h) of SVT 75%, 83% and 93%, and 72%, 86% and 93% in the angiography and total group of patients, respectively (p=NS). Combined analysis of the three noninvasive markers was found to increase the prediction, of coronary artery patency following thrombolytic therapy in, patients with acute myocardial infarction.