Impact of haemodialysis on QTc dispersion in children

Background: The purpose of the present paper was to investigate the corrected QT (QTc) interval and QTc dispersion value, and the impact of haemodialysis on these parameters in children with chronic renal failure. Methods: Nineteen patients with chronic renal failure receiving haemodialysis were included in the present study. Electrocardiography (ECG), echocardiography and serum biochemistry were performed in all patients. Serum electrolyte levels were measured before and after haemodialysis, at the time of the ECG. Nineteen healthy age- and sex-matched children served as the control group. Results: Patients with chronic renal failure had greater QTc interval and QTc dispersion compared to control subjects. The patients' sex, age and presence of hypertension or left ventricular hypertrophy (LVH) were not related to QTc interval/dispersion. However, the patients with left ventricular (LV) systolic dysfunction had significantly greater QTc dispersion value. After haemodialysis session, both QTc interval and QTc dispersion values significantly increased. Serum potassium levels significantly decreased, whereas the calcium level significantly increased after the haemodialysis session. The changes in electrolyte values were not associated with the changes in both QTc interval and QTc dispersion. Conclusion: Children receiving haemodialysis may be at greater risk of ventricular arrhythmia and sudden death because QTc dispersion reflects heterogeneous recovery of ventricular excitability.