Systolic time intervals were obtained from 19 middle-aged noninsulin-dependent diabetic patients without clinically evident cardiovascular disease (8 patients had and 11 did not have retinopathy) and 14 normal subjects using ear densitography. All subjects had neither ischemic electrocardiographic response nor chest pain during maximal treadmill exercise. Although left ventricular ejection time (LVET) and preejection period (PEP) did not differ significantly at rest between the three groups, a prolongation of LVET with a nearly identical PEP response was observed during exercise in diabetic patients with retinopathy. These data indicate that the diabetic patients with retinopathy relied on the enhanced ventricular filling in maintaining stroke volume during exercise. Thus, retinopathy is associated with impaired left ventricular systolic function in noninsulin-dependent diabetic patients.