Parameters of Cardiac Electrical Instability in Chronic Haemodialysis Patients

Abstract

Background: A large proportion of cardiovascular mortality in dialysis patients is caused by sudden death that is related to the dialysis procedure. Parameters of heart rate variability, P wave duration and dispersion and rate corrected QT and QT dispersion are readily used to assess cardiac electrical stability. However, there are relatively few data discussing the factors associated with arrhythmia in dialysis patients. Methods: The study included 30 patients on regular haemodialysis. All patients had full history taking (age, sex, duration of haemodialysis in months and smoking history), clinical examination, laboratory investigations (serum Mg, K, Na and complete blood picture), echocardiography and 24-hours Holter recording. Results: The study included 30 patient on regular haemodialysis (mean duration 30.9±13.2 months), 53.3% males with mean age 43.9±10.1 years. All ECG and Holter derived parameters showed statistically significant changes during haemodialysis. There were increase in P wave duration and dispersion, rate corrected QT interval and QT dispersion and decrease in heart rate variability, that are arrhythmogenic. Moreover, the incidence of both supraventricular and ventricular ectopics increased during dialysis. Smoking and long term dialysis were associated with more arrhythmia risk. Conclusions: Patients on regular haemodialysis are susceptible to cardiac arrhythmias. The process of haemodialysis itself is arrhythmogenic. Smoking and long term haemodialysis are associated with higher incidence of cardiac electrical instability.