Cardiac function and coronary arteriography in asymptomatic Type 1 (insulin-dependent) diabetic patients: Evidence for a specific diabetic heart disease

Abstract

Cardiac function was examined in 63 asymptomatic Type 1 (insulin-dependent) diabetic patients, aged 30–50 years, using radionuclide ventriculography and exercise electrocardiography to investigate the possible existence of a specific diabetic heart disease. Comparisons were made with 45 age- and sex-matched non-diabetic controls. Radionuclide ventriculography was performed at rest and during the physiological stresses of isometric exercise, cold-pressor testing and dynamic exercise. Scans were technically satisfactory in 56 of the diabetic patients and 38 of the control subjects. The resting left ventricular ejection fractions and the responses to isometric exercise and cold-pressor testing were similar in the diabetic patients and controls. A smaller rise in the left ventricular ejection fraction during dynamic exercise was observed in male diabetic patients compared with male control subjects (9±1% (mean±SEM) vs 14±1% (p< 0.005)). A similar trend was observed in female diabetic patients, with a rise of 5±1% on dynamic exercise compared with a rise of 8 ± 1 % in the control group. Sixteen diabetic patients (29%) demonstrated an abnormal response to dynamic exercise, and 5 of these had an abnormal exercise electrocardiogram. Cardiac catheterisation and coronary arteriography were performed in eight of these 16 patients, and all 8 had normal coronary arteries. Endomyocardial biopsy revealed arteriolar thickening and interstitial fibrosis in 5 patients, and in 2 patients basement membrane thickening was conspicuous. Thus, in diabetic patients cardiac function may be abnormal without evidence of coronary heart disease, and some patients appear to have the histological changes consistent with a diabetic microangiopathy involving the heart.