Large potassium shifts during dialysis enhance cardiac repolarization instability

Background Patients with end-stage kidney disease are at high risk for the development of arrhythmias and sudden cardiac death (SCD). This has been especially attributed to large potassium shifts during hemodialysis (HD), and malignant arrhythmias are closely linked to dysfunction of the autonomic nervous system. Nevertheless, there is still a lack of methods for risk stratification in these patients. Methods In the present pilot study we investigated changes of the novel ECG-based biomarker periodic repolarization dynamics (PRD) mirroring the effect of efferent sympathetic nervous activity on the ventricular myocardium in 18 patients undergoing routine hemodialysis. High-resolution ECGs were recorded throughout the dialysis and PRD values were calculated out of 30 min intervals at the start and the end of dialysis. Results We detected a clear correlation between the intradialytic potassium shift and the increase in PRD levels (Spearman correlation coefficientR = 0.62,p = 0.006). Patients with a potassium shift > 1 mmol/l showed significantly increased levels of PRD at the end of dialysis when compared to patients with potassium shifts <= 1.0 mmol/l [delta PRD 2.82 (IQR 2.13) vs. - 2.08 (IQR 3.60),p = 0.006]. Spearman analysis showed no significant correlation between PRD changes and fluid removal (R = - 0.23,p = 0.36). Conclusions We provide evidence that large potassium shifts during HD enhance sympathetic activity-associated repolarization instability. This could facilitate the occurrence of malignant arrhythmias, and PRD measurements might serve as a non-invasive monitoring tool in HD patients in future.