Quantitative evaluation of diabetic autonomic neuropathy by using heart rate variations. Determination of the normal range for the diagnosis of autonomic neuropathy.

Abstract

Heart rate (HR) variations in supine resting position, during deep breathing and on standing, were measured in 162 healthy subjects and 168 diabetics using an instantaneous HR-change continuous recorder. As indices of HR variations, the SD of the HR at rest (SD of HR), the mean difference between maximal and minimal HR during deep breathing (.DELTA.I-E) and the HR increase on standing (.DELTA.HR) were determined. In healthy subjects, the values for each test declined with age and the log-transformed data fitted the linear regression. The 90% confidence limits were calculated for the normal range and values below the normal range were defined as abnormal. In diabetes, the abnormal response incidence were SD of HR 19%, .DELTA.I-E 38%, .DELTA.HR 22%. The .DELTA.I-E was the most sensitive index for the autonomic neuropathy. The .DELTA.HR was considered to be able to detect the different neural reflex mechanisms because of the poor correlation between the .DELTA.HR and the respiratory HR variations. .DELTA.I-E and .DELTA.HR should be measured at the same time to evaluate the autonomic neuropathy.