Cardiac denervation in diabetes.

Cardiac parasympathetic damage is the earliest indicator of cardiac denervation in the diabetic. This was assessed in 35 diabetics by beat-to-beat variation expressed as Maximum-Minimum Heart Rate; 30/15 Ratio and the Standard Deviation of the R-R intervals. Both the 30/15 Ratio and the Maximum-Minimum Heart Rate methods showed good correlation of results and the drawbacks of each method were discussed. Although there was no good correlation between the duration of diabetes and impaired beat-to-beat variation, late complications of diabetes were associated with impaired autonomic function tests. The natural history and the importance of detection of diabetic autonomic neuropathy were both discussed.