Association of exercise-induced, silent ST-segment depression with the risk of stroke and cardiovascular diseases in men

Abstract

Background and Purpose - There are few if any data on the prognostic importance of silent myocardial ischemia during exercise with regard to the risk of stroke and cardiovascular diseases (CVDs) among asymptomatic men. In this prospective study, we investigated the relation of silent myocardial ischemia and the risk of stroke and CVD death in men with and without conventional risk factors. Methods - The study sample included 1726 middle-aged men with no history of stroke, coronary heart disease, or atrial fibrillation at baseline. Silent myocardial ischemia was defined as a horizontal or downsloping ST-segment depression (≥1 mm) during exercise electrocardiography. A total of 86 CVD-related deaths and 78 strokes occurred during an average follow-up of 10 years. Results - Men with silent ischemia during exercise had a 3.5-fold increased risk of CVD death and a 2.2-fold increased risk of stroke compared with men without silent ischemia, after adjusting for conventional risk factors. Silent ischemia during exercise was associated with a 3.8-fold (95% confidence interval [CI], 1.5 to 9.5) increased risk for CVD in smokers, a 3.9-fold (95% CI, 2.1 to 7.3) increased risk in hypercholesterolemic subjects, a 3.6-fold (95% CI, 1.9 to 6.8) increased risk in the hypertensives, and 3.8-fold (95% CI, 2.0 to 7.1) increased risk in overweight men. The respective relative risks for stroke were 3.8 (95% CI, 1.1 to 12.5), 3.5 (95% CI, 1.7 to 7.4), 3.4 (95% CI, 1.6 to 7.1), and 2.9 (95% CI, 1.4 to 6.1). Conclusions - Exercise-induced silent myocardial ischemia is an important indicator of increased risk of stroke and CVD in men with other risk factors, such as smoking, hypercholesterolemia, hypertension, and being overweight.