[Prognosis of silent myocardial ischemia]

Asymptomatic or silent myocardial ischemia (SI) is frequent in coronary heart disease and its prognostic value is controversial. The aim of our study is to compare coronary atherosclerosis, left ventricular function and clinical out come of 110 patients with S.I. (A group) and 210 patients with stable angina (B group). The 320 patients were submitted: to symptom limited exercise stress-test with permanent electrocardiographic control by a Case 12-15 digitalized system with ST segment depression interpretation. A test was considered positive for ischemia if there was ST depression of > 1 mv in magnitude from baseline, persisting for 0.08 sec or exercise angina and ischemia: to selective coronarography by Seldinger technic, with left ventricular cineangiography in 2 incidences. A significant coronary stenosis was defined as > 50% reduction of luminal diameter; to medical treatment with betablockers (87.5% of patients), calcium inhibitors (12.5%), aspirin (90%) and nitrates; to regular medical surveillance. During the follow-up (42.4 +/- 5 months in mean) the number of deaths, myocardial infarctions, heart failure, unstable angina and revascularizations were analyzed. Patients of A group with S.I. had a high percentage of risks factors (diabetes mellitus 55%, nicotinism 85%, dyslipidemia 22.5%) and history of previous myocardial infarction in 33% of cases. There are not significant differences between severity and extension of coronary disease, or ventricular dysfunction in patients of A group or B. The percentages of deaths (2.10 versus 3%), acute myocardial infarctions (9.5 versus 8.5%), heart failures (2.72 versus 3%), surgical indications (14.7 versus 15.7%) are not significantly different between the 2 groups. In A group, 34% of patients were treated by angioplasty versus 40% of patients in group B (p < 0.02). S.I. has a bad prognostic and the clinical out come of coronary heart disease is not dependent of presence of angina during exercise testing and daily activities.