Prevalence, Characteristics and Three Years Prognostic Significance of Silent Myocardial Ischemia during Early Exercise Testing in Patients after the First Myocardial Infarction

The aim of this study was to evaluate the frequency, some characteristics and prognostic significance of silent myocardial ischemia during early exercise testing in patients after myocardial infarction. In the group of 210 patients within three months after myocardial infarction submaximal or symptom-limited exercise test were performed. Out of 210 patients 88 (42%) had ischemic response on exercise electrocardiogram and 2D exercise echocardiogram. Out of 88 patients with ischemic response on exercise electrocardiogram and echocardiogram 54 (61%) had anginal pain or it's equivalents (symptomatic myocardial ischemia) and 34 (39%) had not ischemic symptoms (silent myocardial ischemia). Diabetes mellitus and arterial hypertension was more frequent in patients with silent than in patients with symptomatic myocardial ischemia. Level of exercise test and heart rate at the onset of both types of myocardial ischemia were not differ significantly. Duration of exercise testing was significantly bigger in patients with silent myocardial ischemia. The average magnitude and duration of ST-segment depression in both groups of pts with myocardial ischemia were similar. Before exercise test wall motion score index (WMSI) was similar in both groups of patients. After exercise stress echocardiography WMSI significantly rised in both groups, but more in patients with symptomatic ischemia, and after exercise test WMSI was significantly bigger in patients with symptomatic ischemia. During three years follow-up there were no significant differences in mortality, reinfarction and coronary artery by-pass surgery rate between patients with symptomatic and silent myocardial ischemia. This study showed that: silent myocardial ischemia, during early exercise testing was frequent finding in patients after myocardial infarction, especialy in those with diabetes mellitus and arterial hypertension; there were not significant differences in characteristics between silent and symptomatic myocardial ischemia on exercise electrocardiogram; and three years prognostic significance of both types of myocardial ischemia was similar.