Quantitative Evaluation of Diabetic Autonomic Neuropathy by Using Heart Rate Variations : Relationship between Cardiac Parasympathetic or Sympathetic Damage and Clinical Conditions

Abstract

It was previously suggested that respiratory heart rate (HR) variations were predominantly affected by the parasympathetic nerve and HR increase to standing was predominantly affected by the sympathetic nerve. To compare parasympathetic and sympathetic nerve function in diabetics, these two tests were performed in 95 diabetics and 38 controls by use of an instantaneous-HR-change continuous recorder. All subjects were between 40 and 59 years-old. As indices of autonomic nerve function, the mean difference between maximal and minimal HR during deep breathing (ΔI-E) and the HR increase on standing (ΔHR) were determined. The mean ΔI-E and ΔHR in the diabetics were 9.4 beats/min and 15.1 beats/min, respectively. These values were significantly lower than those in the controls (ΔI-E 14.4, ΔHR 20.5 beats/min). ΔI-E correlated negatively to duration of diabetes and mean fasting blood glucose during the last 6 months in the diabetics, but ΔHR did not correlate to them at all. Diminished ΔI-E was found in the patients with insulin treatment, retinopathy or persistent proteinuria. Diminished ΔHR, however, was found only in the patients with long-standing complicated diabetes. Thus, both cardiac parasympathetic and sympathetic nerve function were significantly impaired in the diabetics as compared with the controls and that parasympathetic nerve damage occurred early whereas sympathetic innervation was preserved. © 1986, Tohoku University Medical Press. All rights reserved.