Effect of haemodialysis on regional and transmural inhomogeneities of the ventricular repolarisation phase.

Recent studies have indicated increased ventricular repolarisation dispersion in haemodialysis (HD) patients. The purpose of this study was to estimate the effect of the HD process on parameters of regional and transmyocardial repolarisation inhomogeneities. Thirty-two selected HD patients (without relevant diseases and medication known to affect the QT interval) were included. Dispersion of the QT corrected interval (QT-c-D) and the corrected interval between the peak and the end of the T wave (Tpe-c-D) were evaluated before and after HD, and in controls. Blood chemistry and extracellular body water (ECW) were evaluated before and after HD. Predialysis QT-c-D and Tpe-c-D were higher in patients (53.40 +/- 17.39 and 47.50 +/- 13.68 ms, respectively) than in controls (34.91 +/- 17.70 ms, p < 0.001 and 31.9 +/- 16.76 ms, p < 0.001, respectively). HD induced an increase in the QT-c-D (67.59 +/- 19.40 ms; p < 0.001) and Tpe-c-D (62.89 +/- 14.33 ms; p < 0.001). Stepwise multiple regression identified the independent risk factors of QT-c-D (the differences between pre- and postdialysis phosphorus, potassium and calcium levels and ECW values) and Tpe-c-D (the differences between pre- and postdialysis phosphorus levels, calcium levels and ECW values) increases, induced by the HD process. The HD process increases regional and transmyocardial repolarisation phase inhomogeneities in HD patients. Changes of phosphorus, calcium and potassium levels plus ECW values seem to be important predisposing factors as far as the increase in ventricular inhomogeneities in HD patients is concerned.