Immediate PTCA following thrombolysis with streptokinase was performed in 46 out of 533 patients enrolled in a multicentre randomized trial of early reperfusion in patients with acute myocardial infarction. Additional effects of PTCA in patients with a residual diameter stenosis in the infarct-related coronary artery of 70% or more after thrombolysis were compared with successful thrombolysis alone in a matched pair analysis. Thirty six pairs of patients were formed identical with respect to the infarct related coronary artery, presence or absence of previous myocardial infarction, total ST segment elevation on the ECG at admission to the trial, and delay between onset of symptoms and hospital admission. PTCA after thrombolysis did not lead to additional limitation of infarct size, nor to further preservation of left ventricular function. Infarction rate during the three-year follow-up was 14% after PTCA versus 30% after thrombolysis alone (P = 0.05). Similarly, patients had less angina or heart failure after PTCA, since on average 128 out of 156 weeks follow-up were symptom free, while this was only 102 weeks after thrombolysis alone (P = 0.03). Immediate PTCA after thrombolysis with intracoronary streptokinase seems to prevent recurrent ischemia and reinfarction. Further studies should address the proper indication and timing of PTCA after thrombolysis.