Variation of kalemia and electrocardiographic predictors of sudden cardiac death along hemodialysis sessions

Introduction Sudden cardiac death (SCD) is the leading cause of death in hemodialysis (HD) patients, accounting for 20 to 30% of mortality in this population. Several electrocardiographic (ECG) predictors of cardiac arrhythmia responsible of SCD were previously defined. However, these predictors were less studied in HD population with divergent results. Purpose The aim of our study is to evaluate different potential ECG predictors of SCD in parallel to kalemia variations in our HD population. Methods We conducted a transversal study including 60 chronically dialysed patients. A kalemia dosage and an ECG recording immediately before and after HD sessions were performed. Then we evaluated, before and after dialysis, the variation of kalemia and ECG parameters: T wave and R wave amplitudes, T/R ratio, corrected QT interval (QTc), QRS duration and U wave. Results Fourty-one males and nineteen females were studied with a mean age of 60 years old. Patients were chronically dialysed for a mean duration of 66 months (12 to 456 months). Diabetic nephropathy was the leading cause of hemodialysis (20%). Along HD sessions, a significant decrease of kalemia from 5.09 ± 0.66 mmol/L to 3.18 ± 0.59 mmol/L was detected ( P  = 0.0001). In parallel, these ECG parameters significantly changed: T wave decreased, R wave increased and, as a result, T/R ratio decreased ( Table 1 ). Conclusion According to our study, we noted that, along HD sessions, with the decrease of kalemia, a significant decrease of T/R ratio occurred which may lead to a potential risk of cardiac arrhythmia and SCD.