Key words: diabetes mellitus, diastolic dysfunction,

microvascular disease SUMMARY Left ventricular diastolic dysfunction is a main feature of diabetic heart disease. The aim of this prospective study was to evaluate the relation of hemoglobin A1c and diastolic function in type 1 diabetes mellitus. We examined echocardiographic studies of 25 patients with type 1 diabetes without clinical evidence of heart disease and 25 healthy age-and sex-matched normal individuals. In patients with type 1 diabetes, there was a diastolic dysfunction with lower transmitral E/A (1.28±0.3 vs. 1.6±0.3; p=0.01), more prolonged isovolumic relaxation time (99±11 vs. 71±8, p=0.003) in comparison with normal subjects. Furthermore, HbA1c correlated with diastolic indices. These results demonstrate that asymptomatic diastolic dysfunction is common in patients with type 1 diabetes mellitus and that its severity correlates with glycemic control