QTC INTERVAL, AND AUTONOMIC AND SOMATIC NERVE FUNCTION IN DIABETIC NEUROPATHY

QTc intervals were measured using an electrocardiogram and other auton omic function tests, in 66 neuropathy patients with non-insulin-depend ent diabetes mellitus (59.0 +/- 12.5 years; mean +/- SD). The change i n R-R interval did not influence the QTc interval, as calculated by th e equation: QTc = QT + (1000-R-R)/7 (ms), compared with the convention al Bazett's equation which appeared to overcompensate in the case of a small R-R interval. The QTc interval in the diabetic patients was sig nificantly longer than that in age-matched controls. The QTc interval showed an inverse correlation with the coefficient of variation of the R-R interval and skin blood flow at rest. However, no correlation was found between QTc interval and blood pressure change, change in heart rate on standing, or results of the sympathetic skin response. The QT c interval did not correlate significantly with motor or sensory nerve conduction parameters. We conclude that the QTc interval can be a sim ple and useful autonomic indicator for diabetic neuropathy relatively independent of other abnormalities of autonomic and somatic nervous sy stem function. Clin Auton Res 8:139-143 (C) 1998 Lippincott-Raven Publ ishers.