Intravenous (IV) fibrinolytic therapy, a recent area of research, has a great deal of applicability in emergency medicine. We report our experience with 30 patients treated with this method. Thirty consecutive patients in the early stages of acute evolving myocardial infarction (AMI) were assigned to receive high-dose IV streptokinase, 1.5 million units over a 30-minute period. Patients presented to the treating hospital at a mean time of 1.21 +/- 1.08 hours, and treatment commenced at a mean time of 2.77 +/- 1.31 hours after the onset of symptoms. Using standard clinical criteria, 86.7% (n = 26) of the patients reperfused initially. Two, however, reoccluded within the first 48 hours, and their clinical symptoms of myocardial infarction reappeared. By clinical observation 80% (n = 24) of the patients reperfused, and myocardial salvage was observed. Twenty-four patients with clinical reperfusion and one additional patient had patency of the affected artery, yielding a reperfusion rate of 83.3% (n = 25) as judged by angiography within one week of AMI. Both patients who had reoccluded clinically also were found to be occluded on angiography. Clinical and angiographic methods yield very similar results for the judgment of reperfusion (80% vs 83%, respectively, with no significant difference, P not significant). The results of our study tend to confirm the efficacy of IV streptokinase as a valuable management tool for early myocardial infarction.