The aim of this study was to evaluate the relations between left ventricular (LV) functional abnormalities, microangiopathy, and autonomic dysfunction in patients with non-insulin-dependent diabetes mellitus (NIDDM). We studied 66 normotensive patients with NIDDM of > or =4 years' duration (age, 51 +/- 4.5 years; 35 men) and no clinical evidence of cardiac disease. Twenty-one healthy subjects matched for age and sex served as a control group. Echocardiography and Doppler studies were performed to assess LV systolic and diastolic function. Microangiopathy was assessed by fundus examination. Autonomic function was assessed by standing blood pressure and heart rate response to Valsalva maneuver. Patients with NIDDM had a lower ejection fraction (58% +/- 11% versus 66% +/- 4%, P <.0001), E-F deceleration slope (382 +/- 75 versus 427 +/- 31 cm/s(2), P <.05), and E velocity (55 +/- 11 vs. 58 +/- 6 cm/s, P =.02) of the mitral diastolic flow, compared with control subjects, respectively. Patients with ejection fraction <50% had a higher prevalence of retinopathy (65% versus 29%, P <.005), abnormal blood pressure response to standing (53% versus 8%, P <.0005), and proteinuria (65% versus 27%, P =.006). An inverse correlation was found between the duration of diabetes and both the ejection fraction (r = -0.53, P <.05) and E/A ratio (r = -0.4, P <.005). E/A ratio <1 was associated with a higher prevalence of retinopathy (49% versus 20%, P =.01) and abnormal blood pressure response to standing (29% versus 4%, P <.005). Patients with NIDDM and no symptoms of cardiovascular disease have a reduced LV systolic and diastolic function as compared with healthy subjects. LV systolic and diastolic abnormalities are correlated with the duration of diabetes and with other diabetic microangiopathies such as diabetic retinopathy and neuropathy.