CARDIAC CONSEQUENCES OF DIABETES-MELLITUS

A variety of disciplines including noninvasive and invasive cardiac me thodologies, as well as epidemiologic studies, have provided informati on that has altered our view on the relation of diabetes to cardiac di sease. Instead of an exclusive focus on coronary artery disease, it is now recognized that heart muscle can be independently involved in dia betic patients. In diabetics without known cardiac disease, abnormalit ies of left ventricular mechanical function have been demonstrated in 40 to 50% of subjects, and it is primarily a diastolic phenomenon. Lef t ventricular hypertrophy may eventually appear in the absence of hype rtension. The diastolic dysfunction appears related to interstitial co llagen deposition, largely attributable to diminished degradation. The presence of even moderate obesity intensifies the abnormality. Revers ibility of this process is not readily achieved with chronic insulin t herapy. Experimental studies have indicated normalization of the colla gen alteration by endurance training, begun relatively early in the di sease process. General measures of management include the control of o ther cardiac risk factors and a reasonable program of physical activit y. The high mortality during an initial acute myocardial infarction ha s been attributed to heart failure, which is managed as in nondiabetic patients. Recently, the early introduction of aspirin, thrombolysis, and beta-adrenergic blockade has reduced mortality during the initial infarction. Chronic use of the latter agent over the subsequent years has also proven to be more beneficial in diabetic patients with acute myocardial infarction compared with nondiabetic patients.