Risk stratification with low-level exercise testing 2 weeks after acute myocardial infarction

Abstract

We enrolled 250 patients with acute myocardial infarction after they had been discharged from the cardiac intensive care unit. Among 236 patients who performed a low-level exercise test just before hospital discharge, 52 (22%) had exercise-induced ST depression of at least 0.1 mV in ECG lead V5, 102 (43%) had ventricular arrhythmias, and 121 (51%) had an exercise capacity of shorter than 6 minutes. We used multiple logistic regression analysis to investigate the association of exercise variables with 1-year cardiac mortality. Exercise duration and ventricular premature depolarizations (VPDs) were significantly associated with 1-year mortality after acute myocardial infarction, both with and without control of the influence of other exercise variables statistically; the association of exercise-induced ST depression with 1-year cardiac mortality was not statistically significant. Standardized regression coefficients showed that the variables ranked in the following order in terms of predictive value: exercise duration, VPD frequency and ST depression. Jackknife techniques showed that multiple logistic regression using the three exercise variables was highly accurate in predicting 1-year mortality.