A NONINVASIVE APPROACH TO CARDIAC AUTONOMIC NEUROPATHY IN PATIENTS WITH DIABETES-MELLITUS

Summary. The purpose of this study was to obtain information regarding the participation of the sympathetic nervous system in cardiac autonomic neuropathy in patients suffering from diabetes mellitus employing spectral analysis of heart rate variability in the supine and standing posture. Ten insulin‐dependent diabetic patients (29 ± 2 years) with a short to moderately long duration of diabetes (11 ± 1 years) and cardiac vagal neuropathy based on measurements of respiratory sinus arrhythmia were compared to 10 healthy volunteers (27 ± 1 years) before and after the administration of atropine and atropine plus propranolol. In diabetic patients the reactivity in total power (ΔTP) from supine to upright position was significantly lower compared to control subjects before and after atropine. There was no significant difference in ΔTP between diabetics and controls after atropine plus propranolol. The magnitude of TP increase is essentially due to the increase of blood pressure related heart rate fluctuations (ΔMF) from lying to standing and dependent on β‐adrenergical efferent activity to the heart. In diabetic patients as well as in normal subjects under the influence of atropine plus propranolol the ΔMF power was significantly lower compared to the un‐medicated control and atropine group. There was no significant difference between diabetics and controls after combined autonomic blockade. It was concluded that ΔMF heart rate spectral power could serve as an indirect, non‐invasive, quantitative and sensitive marker of early cardiac sympathetic damage. Copyright © 1990, Wiley Blackwell. All rights reserved