ANATOMIC BASIS OF LEFT-VENTRICULAR DYSFUN CTION IN PATIENTS WITH INSULIN-DEPENDENT DIABETES-MELLITUS

Introduction and objectives. The natural history of diabetic cardiomyo pathy remains unclear, mainly due to concurrent coronary disease or hy pertension. Since the presence of confounding factors is less Likely i n youngsters, they constitute a suitable study model to analyze early stages of diabetic cardiomyopathy. Patients and methods. We screened 3 3 young normotensive asymptomatic patients with type I diabetes mellit us. Mean age was 28 +/- 8 y (range 18 to 46 y) and there were 14 men. Results. 2-D Echo showed normal left ventricular size and wall motion in all patients but one. Radionuclide basal ejection fraction was 56.5 +/- 6.6% and increased to 63 +/- 7.4% (p < 0.02) on exercise. Accordi ng to Rozansky criteria, 16 patients had an abnormal response. Abnorma l stress sestamibi was detected in 18 patients and only 3 had reversib le defects. Coronary angiography was performed in 11 patients with at least one abnormal non-invasive study response. Coronary angiography r evealed normal vessels in all patients and left anterior descending bl ood now velocity (Doppler) increased 4 fold after papaverine infusion. Left ventricular biopsies showed hypertrophy (either nuclear or cellu lar) in 11, myocitolysis in 6, interstitial fibrosis in 9 and lipid de posits in 4. Morphometric analysis of cardiac samples comparing the di abetic group and a control group showed that the volume fraction of fi brosis (0.19 +/- 0.06 vs 0.10 +/- 0.06; p < 0.01), fiber area -mu(2)- (1,062 +/- 547 vs 600 +/- 167; p < 0.02) and fiber diameter -mu- (24.2 +/- 3.3 vs 15.1 +/- 3.4; p < 0.001) were higher in the former; and vo lume fraction of the myocytes was higher in the latter (0.71 +/- 0.06 vs 0.89 +/- 0.07; p < 0.001). Conclusions. Left ventricular dysfunctio n, not related to coronary atherosclerosis or small vessel disease, is frequent in asymptomatic young diabetic patients. Abnormal pathologic findings are common in the type of cell hypertrophy, interstitial fib rosis, myocitolysis and lipid deposits.