The effects of exercise training on myocardial perfusion during the first 3 months after acute myocardial infarction (AMI) were assessed by exercise myocardial scintigraphy and fibrinolytic examinations. Symptom-limited treadmill exercise with thallium-201 myocardial single photon emission CT (SPECT) and fibrinolytic examinations (tissue plasminogen activator antigen: tPA, plasminogen activator inhibitor-1 antigen : PAI-1) were performed 2 and 14 weeks after AMI in 13 patients with exercise training and in 12 patients without exercise training. For quantitative analysis, counts of region of interest in the infarct area and normal reference area were calculated on a polar map obtained from myocardial SPECT. Severity of the hypoperfused myocardium was determined as an initial percent uptake (%IU) and a delayed percent uptake (%DU). The difference (%DU-%IU) was defined as a parameter of residual ischemia in the infarct area (%redistribution : %RD). Total treadmill exercise duration according to the Bruce protocol increased significantly in the training group (351 +/- 89 to 431 +/- 118 sec, p < 0.01); whereas, there was no significant change in the non-training group (340 +/- 95 to 356 +/- 123 sec). In the training group the pressure-rate product and %DU increased significantly (225 +/- 55 to 259 +/- 58 mmHg.beats/min x 100, 59 +/- 19 to 65 +/- 20%, p < 0.01, respectively), and %RD decreased significantly (8.8 +/- 6.7 to 4.8 +/- 4.5%, p < 0.01), but there was no significant change in the non-training group (231 +/- 89 to 240 +/- 86 mmHg.beats/min x 100, 56 +/- 17 to 57 +/- 12% and 7.4 +/- 5.5 to 6.2 +/- 6.5%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)