The time between coronary artery occlusion and reperfusion remains the decisive factor for myocardial function in acute myocardial infarction. Of 110 patients admitted to hospital less than 3 hours after the onset of chest pain, 83 underwent intracoronary thrombolysis with streptokinase or urokinase. 27 patients underwent mechanical recanalization with the aid of a steerable guide wire (Schneider 0.014") followed by transluminal angioplasty of the residual stenosis. 70 of 83 patients (84%) were recanalized by intracoronary streptokinase perfusion within 45 +/- 10 minutes. By mechanical recanalization the occluded artery could be recanalized in 27 patients within 6 +/- 1 minutes. During the same session transluminal angioplasty was performed while the affected coronary artery was perfused for 20 minutes with 20,000-50,000 U streptokinase. 2 patients died after intracoronary thrombolysis (2.4%) and 1 patient died after mechanical recanalization (3.7%). 25 of 26 survivors of the mechanical recanalization group were discharged after bicycle stress testing, and 1 patient underwent a coronary bypass operation. In the intracoronary thrombolysis group, 4 patients presented with reobstruction of the affected vessel within 24 hours of the intervention (4.8%). Of the remaining 66 patients. 20 underwent transluminal coronary angioplasty (285), 16 coronary bypass (22%) and 30 received drug therapy (43%). Left ventricular injection fraction, measured 24 hours after treatment, was 63 +/- 10% in the mechanical recanalization group and 53 +/- 9% in the intracoronary thrombolysis group.