SILENT-MYOCARDIAL-ISCHEMIA IN DIABETICS WITH NORMAL AUTONOMIC FUNCTION

Twenty male diabetic patients (age range, 40-60 years) with normal aut onomic function were studied to determine the prevalence of silent myo cardial ischemia on exercise as well as ambulatory electrocardiography . The presence and extent of silent myocardial ischemia was also corre lated with the severity of atherosclerotic coronary artery disease as determined by coronary angiography. A cohort of 20 matched non-diabeti c patients were also included in the study. Silent myocardial ischemia was detected in 50% of the diabetic patients on exercise electrocardi ography and in 35% on ambulatory electrocardiography compared with 10% and 5% in non-diabetics by the two methods, respectively (P < 0.01 an d P < 0.05, respectively). On exercise testing in diabetic patients, s ilent myocardial ischemia was detected in 64% of the patients with thr ee-vessel disease, 50% of the patients with two-vessel disease and 20% of the patients with one-vessel disease whereas in non-diabetic patie nts silent myocardial ischemia was detected in only 18% of the patient s with three-vessel disease (P < 0.05) and in none of the patients wit h two- or one-vessel disease. On ambulatory electrocardiography, only patients (both diabetic and non-diabetic) with three-vessel disease ma nifested silent myocardial ischemia. Total ischemic burden was similar in both the diabetic and non-diabetic patients. We conclude that sile nt myocardial ischemia occurs in diabetic patients with coronary arter y disease more frequently even in the absence of autonomic dysfunction and the prevalence of silent myocardial ischemia is higher in patient s with severe degree of coronary artery disease.