Spectral analysis of spontaneous heart rate variation in diabetic patients.

In 28 diabetic patients and 62 control subjects spectral analysis of spontaneous beat-to-beat RR interval variations was performed. The spectral analysis focused on the dominant frequency of the mid-frequency band (0.04-0.12 Hz) or baro-oscillatory phenomenon (BOP). Compared with control subjects the dominant frequency of the BOP (BOP frequency) in the diabetic patients was lower (p less than 0.001), and the difference increased with age. The shift of the BOP frequency was positively correlated with the reduced variation in heart rate during deep breathing (r = 0.80, p less than 0.001) in the diabetic patients. These findings indicate that determination of the BOP frequency is a useful method for assessing cardiovascular autonomic function, supplementary to the known cardiovascular reflex tests. Measurement of the BOP frequency has the advantage that no active patient co-operation is required.