Assessment of diabetic autonomic neuropathy using heart rate monitoring.

Heart rate (HR) monitoring has been used for the diagnosis of diabetic autonomic neuropathy (AN). Two tests were used: measurement of heart rate variation (HRV) during deep breathing and measurement of HR changes on standing up. Three-hundred and one diabetics between 20 and 49 years old were studied, and 21 of them were observed repeatedly over 3-5 years. HRV on deep breathing was the most sensitive diagnostic test of AN, and was abnormal in 84% of 64 patients with established autonomic symptoms. Autonomic abnormalities were also detected in diabetics without autonomic symptoms, especially those with peripheral neuropathy. Abnormal tests represent permanent autonomic damage and may be present for several years before the development of autonomic symptoms. Occasionally they represent the earliest manifestation of diabetic neuropathy.