Pathogenesis of cardiac dysfunction in diabetes mellitus.

The use of insulin by diabetics has largely removed the threat of death from ketotic coma but cardiovascular dysfunction remains a major cause of death in patients with diabetes. Recent research has indicated a generalized membrane defect, which may cause abnormalities of calcium metabolism in nerves, cardiac and smooth muscle as well as endothelial cells and thus may lead respectively to the development of neuropathy, primary cardiomyopathy, microangiopathy and atherosclerosis in the diabetic population. Each of these pathogenic processes, which are associated with insulin deficiency, alone or in combination with others, may result in cardiac dysfunction in chronic diabetes. Activation of the sympathetic nervous system and abnormalities in catecholamine metabolism have been identified in diabetes; their involvement in the genesis of cardiac pump failure as well as large and small vessel disease is likely. The membrane defects as indicated by changes in both plasma membrane and glycocalyx in diabetic cardiomyopathy appear to be complex and may involve alterations in the metabolism of lipids and pyrimidine nucleotides. It seems that intracellular calcium overload is intimately involved in the development of diabetic cardiomyopathy; however, a concentrated research effort is required to understand the primary biochemical lesion in the pathogenesis of cardiac dysfunction in diabetes. In the meantime, a heightened awareness on the part of clinicians concerning the susceptibility of diabetic patients to cardiovascular problems may help in reducing mortality and morbidity in the diabetic population.