Studies of heart rate oscillations in diabetics at rest.

Variation in electrocardiographic R-R intervals during rest was investigated as a measure of autonomic function and as a diagnostic tool in diabetes. Diabetics (106) of both sexes with different duration of the disease were compared with 116 metabolically healthy control subjects of the same age range. Diabetic retinopathy was diagnosed using fundus photography, and classified in stages O-II. Coefficient of variation (CV) of R-R intervals in controls is age-dependent. The negative correlation between CV and age in diabetics applied only when retinopathy was absent; in diabetics with late complications, CV was significantly lower (p less than 0.0001) than in the healthy or in uncomplicated diabetic state. The CV decreased with increasing severity of retinopathy permitting routine differentiation of progressive stages of retinopathy and peripheral neuropathy.