Left ventricular diastolic dysfunction in normotensive diabetic patients in various age strata

Although patients with type 2 diabetes demonstrate cardiac diastolic dysfunction, it is well known that cardiac diastolic dysfunction is produced by hypertension and aging. The purpose of the present study was to elucidate the cardiac structure and function in normotensive patients with type 2 diabetes in various age strata in order to assess the effect of diabetes mellitus itself on cardiac function. Echocardiographic examination was performed in 77 normotensive patients with type 2 diabetes (age: 63+/-11 years) and 76 healthy control subjects (age: 60+/-11 years) who were in their forties, fifties, sixties, and seventies. The left ventricular (LV) wall thickness and dimension were measured by M-mode echocardiography. The relative wall thickness, LV mass index, and LV ejection fraction (LVEF) were calculated. LV diastolic function was assessed by the peak velocity of early rapid filling (E velocity) and the peak velocity of atrial filling (A velocity), and the ratio of E to A (E/A) using the transmitral flow velocity, which were obtained by Doppler echocardiography. No difference was observed in the relative wall thickness, LV mass index, or LVEF between the diabetic patients and control subjects in any of the age strata. The E/A ratio in the patients with type 2 diabetes was not different from that in the control subjects in their 40s (1.17+/-0.35 versus 1.20+/-0.36). However, E/A was significantly lower in the diabetic patients than in the control subjects in their 50s (0.87+/-0.28 versus 1.14+/-0.24), 60s (0.78+/-0.22 versus 0.97+/-0.27), and 70s (0.66+/-0.19 versus 0.84+/-0.21) (p<0.05). The duration of type 2 diabetes was significantly longer in patients in their 50s (7.0+/-2.5 years), 60s (8.0+/-3.2 years), and 70s (10.4+/-3.2 years) than in patients in their 40s (3.3+/-1.9 years) (p<0.001). The value of E/A in the diabetic patients correlated with the duration of type 2 diabetes (r=-0.62, p<0.001). These results indicate that cardiac diastolic dysfunction without LV systolic dysfunction in patients with well-controlled type 2 diabetes is related neither to hypertension nor LV hypertrophy, but rather to aging and the duration of type 2 diabetes.