The postmortem findings and clinical records of 27 patients with proved diabetic glomerulosclerosis were examined and reviewed for evidence of primary myocardial disease. Twenty-three cases were excluded because of complicating conditions such as hypertension, significant obstruction of the major coronary arteries or valvular disease. Four patients demonstrated cardiomegaly and congestive heart failure of no known cause.

The autopsy findings consisted of left ventricular hypertrophy and, in 1 case, right ventricular hypertrophy as well, in the absence of major coronary artery disease. Histopathologic study revealed diffuse fibrotic strands extending between bundles of muscle fibers and myofibrillar hypertrophy. In 1 case, the small intramural coronary arterioles demonstrated thickening of the wall and narrowing of the lumen due primarily to the deposition of acid mucopolysaccharide material in the subendothelial layers and subsequent subintimal thickening and medial hypertrophy.

It is postulated that the myocardial disease seen in these cases is probably secondary to diabetic mjcroangiopathy although the direct effects of the abnormal myocardial metabolism in diabetes could not be excluded.