QT dispersion in the electrocardiogram in hemodialysis and peritoneal dialysis patients

To evaluate QT dispersion (QTd) in dialysis patients in an analytic cross-sectional study, three groups were enrolled: Hemodialysis (HD), peritoneal dialysis (PD) and control (30 patients in each group) to study QT parameters in 12-lead electrocardiograms (ECGs). QTd was calculated (maximum QT interval minus minimum QT interval in different leads in each ECG). In dialysis patients, left ventricle mass index (LVMI) was also evaluated using the ECG of the patients. QT, corrected QT (QTc), QTd and QTc dispersion were significantly higher in the HD and PD groups than in controls, but there was no difference between the dialysis groups. There was no difference between the HD and the PD groups in LVMI and ejection fraction. In the PD group, there was a positive correlation of LVMI and QTd (r = 0.5, P = 0.004) and QTc dispersion (r = 0.54, P = 0.004). We conclude that the QT changes were more prominent in HD and PD patients than in controls, which could be due to electrolyte changes. Further studies to evaluate the causes of the QT changes in a larger population are needed.