With the purpose of ascertaining the predictive value of residual myocardial ischemia, in stable clinical conditions at a distance after myocardial infarction, on the incidence of late cardiac events, we evaluated 55 patients 24.2 +/- 11.4 months after myocardial infarction with thallium-201 stress test imaging. All patients were either asymptomatic or with stable effort angina pectoris, well controlled with medical treatment. In the next follow-up period, whose duration has been 22.4 +/- 14.4 months, the incidence of unfavourable cardiac events, like unstable angina, reinfarction, coronary bypass surgery, sudden cardiac death has been monitored. Thirty-one patients (56.4%) presented a reversible perfusion defect (RPD) in one or more myocardial segments; 17 of these 31 showed cardiac events during follow-up. Only 2 patients of the remaining 24 without RPD had cardiac events, with a significant difference (p less than 0.01). The patients with RPD only in peri-infarct areas had a relatively smaller number of cardiac events, with respect to those patients with RPD also or only in distant areas. Fifteen of 21 patients with RPD in 2 or more segments manifested cardiac events, compared to 2 of 10 patients with RPD in only one segment (p less than 0.01). In 10/55 patients, increased lung uptake of thallium-201 activity was observed; 8 of them presented cardiac events (p less than 0.01). This analysis confirms the high predicting value of thallium-201 RPD imaging on the incidence of cardiac events in patients controlled at a distance after myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)