QTc Interval Changes in Hemodialysis Patients

Sudden cardiac death (SCD) is the leading cause of death in hemodialysis. On hemodialysis, arrhythmias can occur during and shortly after receiving treatment, independent of traditional cardiovascular risk factors. Calcium, potassium, and magnesium may contribute to the development of arrhythmias during hemodialysis as these cations play a major role in development of the ventricular action potential and propagation of the electrical impulse. The optimal serum calcium range, and type of calcium measurement remains unclear, but KDOQI recommends that the dialysate calcium concentration be decreased as a means to maintain neutral or negative calcium balance and prevent vascular calcification. During hemodialysis, serum-ionized calcium varies directly with the dialysate calcium concentration, so a potential harmful effect of reducing calcium concentrations in the dialysate and serum of hemodialysis patients may lead to an increased risk of cardiac rhythm disturbances and sudden cardiac arrest (SCA). Changes in serum calcium, in turn, strongly affect the length of the QT interval so, such disparity in repolarization can be assessed by measuring the QT dispersion, that is, the variation in QT interval length, on a standard 12-lead electrocardiogram. This procedure has been shown to be a useful and reliable means of identifying patients at risk of ventricular arrhythmias. Accordingly, The present study is designed to evaluate the effect of dialysate calcium concentration on cardiac electrical stability during hemodialysis treatment by measuring the QT interval and QT dispersion before and after hemodialysis sessions, each with a different concentration of dialysate calcium.