Diastolic time in diabetes. Impairment of diastolic time during dynamic exercise in type 2 diabetes with retinopathy.

To evaluate the effect of microangiopathic complications and autonomic dysfunction on diastolic time (DT) during dynamic exercise, 19 patients with type 2 diabetes and ten normal subjects were studied using ear densitography. All subjects had neither an ischemic electrocardiographic response nor chest pain during maximal treadmill exercise. The DT and heart rate (HR) had an inverse nonlinear relation, and electromechanical systole (QS2) and HR had an inverse linear relation during exercise. When the exercise DT-HR and QS2-HR relations were compared, a significant lengthening of QS2, with a consequent shortening of DT, was observed in diabetic patients with retinopathy, compared to patients without retinopathy and normal subjects (p less than 0.005), while no significant differences were found between diabetic patients without retinopathy and normal subjects; however, there were no significant differences in the exercise DT-HR and QS2-HR relations among diabetic patients with and without autonomic dysfunction and normal subjects. A more prominent abbreviation in the diastolic perfusion time observed in patients with retinopathy would be meaningful because microangiopathy might already have limited subendocardial blood flow. Thus, patients with type 2 diabetes who have retinopathy have a potential risk of aggravation of left ventricular function through the deterioration of myocardial blood flow.