To determine whether the severity of residual coronary artery stenosis immediately after thrombolytic therapy influences the size of later left ventricular (LV) asynergic area, we reviewed coronary angiograms (CAGs) and left ventriculograms (LVGs) of 31 patients with acute myocardial infarction (AMI). All patients received intracoronary urokinase therapy within 6 h after onset of AMI due to total occlusion of the proximal left anterior descending coronary artery (LAD). A dose of 960,000 IU urokinase was infused into the ostium of the left coronary artery over 40 min. Patients in whom antegrade blood flow without delayed distal filling was restored received rigorous anticoagulation. The patients were divided into three groups according to the severity of the coronary lesion immediately after urokinase therapy: 9 patients with complete occlusion in Group 1, 15 with > 90% stenosis in Group 2, and 7 with < 90% stenosis in Group 3. There were no significant differences in the baseline clinical characteristics among the patients in the three groups. The LADs in Group 1 were also totally occluded 1 month after urokinase therapy, the treated vessels in both Groups 2 and 3 were still patent, and patients in Group 2 showed a further reduction in residual stenosis. When LV asynergic area, regional wall motion, and global ejection fraction (EF) were compared among the three groups, no significant differences were demonstrated. In comparison with the data immediately after urokinase therapy, all parameters 1 month after therapy were significantly improved in both Groups 2 and 3.(ABSTRACT TRUNCATED AT 250 WORDS)