Prevalence and significance of left ventricular filling abnormalities determined by Doppler echocardiography in young type I (insulin-dependent) diabetic patients

Abstract

In 16 insulin-dependent diabetic patients, 36 ± 8 years old with no microangiopathy, hypertension or coronary artery disease, and 16 healthy control subjects matched for sex, age and body surface area, the following parameters were obtained by Dopplerechocardiography: (1) end-diastolic left ventricular thickness and radius; (2) aortic pulse wave velocity; (3) mitral flow with measurement of early and late (atrial) peak velocities (E and A), pressure half-time and the velocity time integrals of the entire mitral curve and of the atrial wave; and (4) isovolumic relaxation time (i.e., the time between aortic closure and the mitral opening signals recorded simultaneously by continuous-wave Doppler). Heart rate and systolic blood pressure were not different in the 2 groups. Aortic pulse wave velocity and the wall thickness to radius ratio were significantly increased in the diabetic patients compared to the controls. E was significantly reduced whereas A E , pressure half-time, the atrial contribution to the left ventricular filling (i.e., the ratio of the atrial velocity time integral to the mitral velocity time integral) and the isovolumic relaxation time were significantly increased in the diabetic group versus the control subjects. Lastly, 11 of 16 diabetic patients (69%) had at least 2 of the following abnormalities: A E >0.71 , an atrial contribution to the left ventricular flung >0.25, a pressure halftime >50 ms and an isovolumic relaxation time >88 ms. No correlations were found between the wall thickness to radius ratio, aortic pulse wave velocity and the filling indexes. In young insulin-dependent diabetic patients with no microangiopathy or coronary artery disease, Doppler filling abnormalities are frequent, and do not depend on the left ventricular geometry or the physical properties of the aorta. These abnormalities reflect changes in myocardial relaxation and may be early markers of diabetic cardiomyopathy.