The incidence of recurrent ischemia, congestive heart failure and death during the first year after discharge were analysed prospectively in a group of 312 patients randomized double blindly to rt-PA (n = 156) or placebo within 5 hours after the onset of acute myocardial infarction. The in-hospital mortality was 4.4% in the rt-PA and 6.4% in the placebo group; the total-mortality after a follow-up of 16 months was respectively 7.6 and 9.6%. During 16 months follow-up reinfarction occurred in 5.4% of the rt-PA treated patients versus 0.0% in controls (p = 0.004). Revascularization was required in 17% of the population (24% in rt-PA versus 16% in controls, N.S.), angina at rest and congestive heart failure, demanding hospitalization developed in 5.1% of the patients (5.3% in rt-PA versus 4.7% in controls, N.S.) and 3.4% of the patients in each group died after discharge. A logistic model constructed to predict event-free survival showed that enzymatic infarct size, exercise capacity and the hemodynamic response at a predischarge bicycle exercise test and end-systolic volume at 2 weeks were predictors of new events. Considerable overlapping between patients with and without a new event was observed.