BACKGROUND: Diabetes mellitus is a chronic and very common condition, and there has been lately a considerable increase in its prevalence and incidence. Diabetic patients have increased cardiovascular mortality, in which malignant ventricular arrhythmias seem to be implicated. OBJECTIVE: To study the effects of diabetes on ventricular repolarization parameters responsible for an increased susceptibility to malignant ventricular arrhythmias and/or sudden death. METHODS: We selected a group of 110 diabetic patients and a group of 110 controls with the same distribution of age, gender and race. We evaluated the following parameters of ventricular repolarization: QTmax, QTmean, QTmin, QTc max, QTc mean, QTc min, QT and QTc dispersions, Tpeak-Tend and jTpeak-jTend intervals (D II, V2 and V5), Tpeak-Tend and jTpeak-jTend dispersions. The electrocardiograms (ECG) were performed by the same operator and reviewed by the same observers. QT intervals were corrected according to Bazzet's formula. RESULTS: We found significantly higher values of QTc max (p < 0.001), QTc mean (p < 0.001), QT dispersion (p < 0.001), QTc dispersion (p < 0.001), Tpeak-Tend dispersion ( p < 0.001), and jTpeak-jTend dispersion (p < 0.001) in diabetic patients than in controls. In diabetic patients, we observed prolonged values of QTc interval (5.5%), QT dispersion (0.9%), QTc dispersion (0%), Tpeak-Tend interval (7.3%), jTpeak-jTend interval (6.4%), Tpeak-Tend dispersion (16.4%), and jTpeak-jTend dispersion (12.7%). In the controls there were no prolonged values of any of the parameters. CONCLUSION: We concluded that diabetes causes prolongation and spatial dispersion of repolarization, and it may contribute to a greater ventricular electrical instability, whose expected clinical expression may be malignant ventricular arrhythmias.
Arrhythmias cardiac; diabetes mellitus; electrocardiography; death; sudden; cardiac
