Abstract The purpose of this prospectively conducted study was to determine the prevalence of transient myocardial ischemia, evaluated from 24 h continous ECG monitoring and exercise test, 6 months after inclusion in the Anglo Scandinavian Study of Early Thrombolysis (the ASSET trial, a randomised, placebo controlled study of alteplase for survival in patients with suspected acute myocardial infarction (AMI)), and to relate these findings to development of cardiac events. Of the 58 consecutively studied patients ischemic responses were found in 13 (45%) of 29 patients initially treated with placebo, and in 21 (72%) of 29 alteplase treated patients ( P = 0.03). After another 6 months, i.e. 12 months after the acute event, two patients were dead, two had non-fatal reinfarctions and three had coronary artery by-pass surgery in the group with ischemic response; no events were recorded in patients without ischemia ( P < 0.05). Alteplase treated patients more often had late myocardial ischemia, and cardiac events were found in patients with ischemia. Since the ASSET trial has demonstrated significantly higher short- and long-term survival rate in the alteplase treated group, it was indicated (1) that alteplase treated patients were better positioned for sustaining subsequent ischemia and thus cardiac events due to preservation of viable myocardial tissue, and (2) that late ischemia in the setting of initial alteplase treatment may convey other information than ischemia occurring in placebo treated patients.