The effects of different electrolyte composition in dialysate on QTc interval; a controlled trial

Introduction: Hemodialysis (HD) has impact on the cardiovascular system by inducing changes in the characteristics of body fluids such as PH, temperature and electrolyte concentrations. In the previous studies, prolongation of the QT interval and increase of QT dispersion have been reported during HD sessions. These changes were more significant while using solutions with less potassium and higher bicarbonate during dialysis. Objectives: The aim of our study was to investigate the effects of different potassium and bicarbonate concentrations on electrocardiography (ECG) parameters and the electrochemical balance of cell membranes. Patients and Methods: This is a double blind controlled clinical trial with crossover design. This interventional study has been conducted on 36 patients over 18 years who undergoing HD 3 times a week for at least 6 months. Twelve-lead ECG has been obtained before starting and one hour after end of each HD session. The QTc was measured and changes recorded by a cardiologist. Correlations were evaluated by univariate regression analysis. Results: 54.38 years (16 to 77 years), 66.7% were male. No significant increase in QT interval has been seen while dialyzing with 2 meq/l potassium and 24 meq/l bicarbonate, 2 meq/l potassium and 28 meq/l bicarbonate and 3 meq/l potassium and 24 meq/l bicarbonate beside high calcium (2.5 meq/l) dialysate was conducted. Age, gender, serum calcium and serum bicarbonate level before HD session did not influence the mean QT intervals before and after dialysis. Conclusion: Concentration of potassium beside moderate dose of bicarbonate in dialysis bath had not any significant influence on QT intervals after dialysis.