Hemodiafiltration beneficially affects QT interval duration and dispersion compared to hemodialysis

The prolongation of the QT interval and dispersion could predict ventricular arrhythmias. It is not yet established whether there is a difference between the effects of hemodialysis and hemodiafiltration on QT interval duration and dispersion.

Data of thirty patients was investigated while they were receiving hemodiafiltration over a period of 3 months; then the same group of patients was evaluated during treatment with conventional hemodialysis for at least another 3 months. Ionic parameters and surface electrocardiograms (ECG) were analyzed five times during each session, and 2D, M-mode echocardiography and Holter ECGs were performed to acquire additional information.

QT interval duration (QTmax) and dispersion (QTd) showed a significant increase during hemodialysis, but not during hemodiafiltration. QTmax was 388.66 ± 31.81 ms at the beginning of hemodialysis and increased to 400.66 ± 39.12 ms even at the 30th minute (p < 0.05). QTd was found to be 31.33 ± 10.08 ms before the commencement of hemodialysis with the largest prolongation being seen at the 240th minute (51.33 ± 14.56 ms, p < 0.05). The occurrence of ventricular premature beats was significantly higher during hemodialysis (p = 0.018). The left atrial diameter significantly decreased at the end of hemodiafiltration (at the beginning 45.1 ± 5.25 mm, at the end 40.77 ± 5.76 mm; p < 0.05).

Our results suggest a beneficial effect of hemodiafiltration on the studied electrocardiographic parameters compared to hemodialysis. The larger decrease in the left atrial diameter suggests a more efficient intracardiac volume-decreasing potential of hemodiafiltration.