BackgroundThe rate of sudden cardiac death (SCD) for hemodialysis (HD) patients is significantly higher than that observed in the general population and have the highest risk for arrhythmogenic death. In this study, we examined serial electrocardiography (ECG) data in patients undergoing HD and determined their associations with the occurrence of SCD.Method In the retrospective review of three tertiary referral hospitals from November 1986 to November 2016, Patients starting HD in each hospital were enrolled; they underwent regular check-ups at least twice a Measurements and Main Results Of 678 enrolled subjects who underwent serial ECG before and after HD, 291 died and 39 developed SCD. In the pre-HD ECG, SCD patients had significantly longer QT peak-to-end (QTpe) intervals in all leads (II, III, aVF, and V1-6, P<0.001) and a longer QRS duration (92.6±14.0 vs. 100.6±14.9 ms, P=0.015) than survivors. However, in the post-HD ECG, there were no significant differences in any of the variables (QTpe interval at all leads, QRS duration, and proportion of patients with atrial fibrillation) that showed differences in the pre-HD ECG analysis. Moreover, the SCD group showed a significant change in the QTpe interval of the inferior, anterior, and lateral leads before and after HD compared with the survivor group (all leads, P<0.001). A cut-off value of 148.1 ms for the QTpe interval at the V2 lead in pre-HD was determined using receiver operating characteristic curve analysis, and QTpe intervals >148.1 ms were significantly associated with SCD after adjusting for age and sex in multivariable analysis (hazard ratio: 5.675, confidence interval: 2.373–13.575).Conclusions In end-stage kidney disease patients, the QTpe interval at all leads and QRS duration were shortened after HD. Patients with a longer QTpe interval before HD and large changes in ECG parameters after HD might be at a higher risk of SCD. Therefore, changes in the ECG before and after HD could help to predict SCD.