QT DISPERSION AND AUTONOMIC NERVOUS-SYSTEM FUNCTION IN PATIENTS WITH TYPE-1 DIABETES

Cardiac arrhythmias and markedly increased mortality rate have been de monstrated in patients with diabetic autonomic neuropathy. Abnormal pr olonged QT dispersion interval (QTd) is associated with a higher risk of ventricular arrhythmias. The aim of this study was to evaluate the relationship between autonomic dysfunction, QT and JT interval dispers ion parameters and ventricular arrhythmias. Twenty-six patients with t ype 1 diabetes mellitus and 20 healthy subjects as controls were enrol led in the study. Resting 12-lead electrocardiograms were recorded for measurement of QTd, corrected QTd (QTcd), JT dispersion (JTd) and cor rected JT dispersion (JTcd). After taking EGG, all patients underwent autonomic function tests. Patients and control group were also evaluat ed by 24-h Holter monitoring. Fourteen patients were identified who ha d autonomic dysfunction. QTd, QTcd, JTd, and JTcd values were signific antly higher in patients with autonomic dysfunction than both patients without autonomic dysfunction and the control group (QTd: 78+/-16 vs. 51+/-13 ms, P=0.002; 78+/-16 vs. 48+/-9 ms, P<0.001; QTcd: 91+/-14 vs . 66+/-12 ms, P=0.001; 91+/-14 vs. 61+/-11 ms, P<0.001; JTd: 81+/-12 v s. 58+/-13 ms, P=0.001; 81+/-12 vs. 49+/-7, P<0.001; JTcd: 96+/-15 vs. 73+/-11 ms, P<0.001; 96+/-15 vs. 67+/-8 ms, P=0.001). There was no si gnificant difference between the dispersion parameters in diabetic pat ients without autonomic dysfunction and the control subjects (P>0.05). Also, patients with autonomic dysfunction had higher Lown classes of ventricular arrhythmias and patients with higher Lown classes of ventr icular arrhythmias had mon prolonged QTd and QTcd values. The data sug gest that diabetic patients with autonomic dysfunction have increased dispersion of ventricular refractoriness, which may be one of the fact ors contributing to the increased incidence of arrhythmias and sudden death observed in these patients. (C) 1998 Elsevier Science Ireland Lt d.