Résumé
The present study was designed to throw light on Q-T interval in patients with type I diabetes mellitus and on its relationship to the cardiac autonomic neuropathy [CAN]. Fifteen healthy subjects as a control group with mean age of 46 +/- 8 years [9 males, 6 females] and 30 patients with mean age of 48 +/- 7 years [19 males and 11 females] were participated in the study. Their electrolyte balance was within normal. Patients with other medical or cardiovascular diseases were excluded. No drugs that may affect Q-T interval and/or autonomic nervous system were being administered. All subjects underwent clinical examination, fasting and post-prandial glucose level, Q-Tc interval determination and autonomic function tests. It was found that 15 out of the 30 patients [50%] had CAN. All patients with CAN but none without CAN had prolonged Q-Tc interval exceeding 440 m.sec.Patients with CAN showed a significant prolongation of Q-Tc interval compared with both control subjects and patients without CAN, whereas, no significant difference was reported between control subjects and patients without CAN. Q-Tc interval showed a positive correlation with both the extent of CAN and the duration of diabetes. So an abnormal resting Q-Tc interval may be objective evidence for CAN and the longer the resting Q-Tc interval, the more severe the CAN. Serious ventricular arrhythmias associating Q-Tc interval prolongation may be a possible explanation for sudden unexplained death in these patients. Finally ambulatory ECG monitoring may be recommended and drugs that are known to prolong Q-T interval should be avoided in such patients