The effect of early perfusion after intracoronary infusion of urokinase (PTCR) in patients with acute myocardial infarction was assessed. Coronary perfusion was reestablished in 7 of 10 patients receiving intracoronary urokinase. We compared the recanalized group after intracoronary urokinase (n = 7) with the standard therapy group (n = 32). Left ventricular end-diastolic pressure, cardiac index, angiographic ejection fraction, radionuclide ejection fraction, defect score by Thallium-201 scintiscan and regional ejection fraction by the left ventriculogram, measured at about one month after the onset of acute myocardial infarction, were compared according to the site of the main coronary lesion (right coronary artery or left anterior descending coronary artery). No statistically significant differences between the recanalized group after the administration of intracoronary urokinase and the control group were found at each coronary lesion. On the other hand, the comparison between two patients with and without PTCR, who matched the clinical and coronary angiographic findings, showed that PTCR on acute myocardial infarction might be of value. However, evaluation of the long-term effects of coronary thrombolysis on survival and myocardial function will require controlled randomized trials of a large number of patients.