Patients with complex arrhythmias during and after haemodialysis suffer from different regimens of potassium removal

Background. Although sudden death is one of the most frequent causes of death in haemodialysis (HD) patients, the problem of cardiac arrhythmias, the major cause of these outcomes, has been little discussed. Methods. In 30 arrhythmia-prone HD patients, we compared the arrhythmogenic effects of two dialysis techniques differing in dialysate potassium (K) content. Each patient underwent Acetate-Free Biofiltration sessions with constant (2.5 mEq/l) K (AFB) and sessions with decreasing intra-HD K (AFBK), according to a crossover single blind design. Holter ECG recording and plasma electrolyte measurements were performed during each dialysis session. Results. There was a tendency in the whole sample for arrhythmia appearance in AFBK to be reduced as compared to AFB throughout the 24 hr period, although this reductionwasnotstatisticallysignificant.Inthesubsetofpatients sensitive to dialysis as far as arrhythmia onset is concerned, AFBK was systematically less arrhythmogenic than AFB (P < 0.01). The highest difference was achieved around the 14th hour after the end of dialysis, when the premature ventricular contractions in AFB were 3.9 times higher than in AFBK (P < 0.05). Potassium kinetics differed between the two procedures. At the first hour of treatment, the plasma K concentration was lower in AFB than in AFBK (3.67 ± 0.15 mEq/l in AFB vs 4.06 ± 0.13 mEq/l in AFBK, P = 0.05). Conclusions. Our study shows a greater arrhythmogenic activity with the use of a constant and relatively low K concentration as compared to decreasing K profiling in dialysis-sensitive arrhythmic patients. Smoother K removal may well engender a kind of protective effect.