Predischarge maximal exercise test identifies risk for cardiac death in patients with acute myocardial infarction

Abstract

A maximal exercise test was performed in 54 patients with acute myocardial infarction (AMI) before discharge and in 49 age-matched control subjects. The long-term prognosis was assessed after an average follow-up of 7.6 years in AMI patients and 5.8 years in control subjects. The maximal work capacity and systolic blood pressure increase in AMI patients was 59% that of control subjects (p < 0.001). Seventeen AMI patients had significant ST-segment shifts, 13 with ST depression and 4 with ST elevation. In AMI patients experiencing a cardiac death during follow-up the maximal work capacity and systolic blood pressure increase were significantly tower than in survivors and those who died from noncardiac reasons (p < 0.01; p < 0.05), with no difference between these groups in the number of patients with ST-segment shifts. The average maximal work capacity of control subjects was 143 watts. A maximal work capacity half this (<-72 watts) predicted long-term mortality in AMI patients (p < 0.001). In addition a low increase in systolic blood pressure (< 30 mm Hg) also predicted long-term mortality (p < 0.005), whereas ST shifts were of no significant value. In this study maximal work capacity turned out to be the best single exercise variable for identifying groups of AMI patients with very low and relative high risk of cardiac death. When all 3 exercise variables were combined, the predischarge maximal exercise test was of great value in identifying AMI patients at low risk for cardiac death (predictive value of a negative test: 95%).