Abstract

BACKGROUND
Diabetic patients with autonomic dysfunction have worse prognosis, including an increased incidence, of sudden death, than those without autonomic dysfunction. This event may be due to sympathetic imbalance causing disturbances of ventricular repolarization. QT dispersion have recently been demonstrated to reflect dispersion of ventricular refractoriness and is a marker of arrhythmogenic potential. METHODS: Sixty diabetic patients and 31 normal subjects were studied. All patients had clinical test for cardiovascular autonomic dysfunction by Ewings method and defined as normal, early involved, definitely involved, severely involved and atypical group for 5 validated tests. Resting standard 12-lead electrocardiograms were recorded for measurement of QT dispersion, defined as the difference of longest QT interval and shortest QT interval, and corrected for heart rate using Bazetts formula. RESULTS: Twenty-seven dIiabetic patient were abnormal in cardiovascular autonomic function tests. In these patients corrected QT dispersion (QTc) were significantly longer compared to that 33 patients without autonomic dysfunction(47.4+14.7 vs 22.6+ 8.1msec p<0.001). And also there was significant difference of QTc dispersion between normal subject and diabetic patients with autonomic neuropathy group(20.5+9.2 vs 47.4+14.7msec p<0.001). But there was no difference between normal control and diabetic patients without autonomic neuropathy group. And QTc dispersion was not related to the presence ot nephropathy, retinopathy or peripheral polyneuropathy. We also found that there was no relationship between the severity of autonomic neuropathy and degree of Q7c dispersion. CONCLUSION: We concluded that QTc dispersion may be a good method for evaluation of cardiovascular autonomic neuropathy and increased QTc dispersion may be one of the markers of arrhythmia in diabetic patients with autonomic neuropathy.

• Keywords: Diabetes mellitus;Autonomic neuropathy;QTc dispersion;