The clinical factors' prediction of increased intradialytic QT dispersion on the electrocardiograms of chronic hemodialysis patients.

Ventricular arrhythmias and sudden death are common in patients on maintenance hemodialysis (HD). The increase in QT dispersion (QTd) on the electrocardiogram (ECG) reflects increased tendency for ventricular repolarization that predisposes to arrhythmias. The purpose of the study was to identify the clinical factors that may predict the increased intradialytic QTd and to assess differences in QTd before and after HD. Each of 61 chronic HD patients underwent 12-lead ECG and blood pressure (BP) measurement before and every 1 h during a single HD session. The QT intervals were corrected for heart rate using Bazett's formula. Intradialytic QTd increased in 30 (49%) patients. There was no correlation between the increased QTd and the clinical factors including hypertension, pulse pressure, intradialytic hypotension, left ventricular hypertrophy, old myocardial infarct, diabetes mellitus, and nutritional status. The means of QT interval and QTd increased after HD session (from 382 ± 29 to 444 ± 26 ms, P <0.05; and from 74 ± 21 to 114 ± 53 ms, respectively, P <0.05). We conclude that the increased intradialytic QTd could not be predicted by any of the clinical factors evaluated in this study. There was significant difference in the means of QTd before and after HD session.