Association of serum electrolyte changes during haemodialysis with stimulation of premature ventricular contractions

Background Patients on haemodialysis are predisposed to heart rhythm disorders, including bradyarrhythmia, atrial fibrillation (AF)/atrial flutter, supraventricular/ventricular arrhythmias and sudden cardiac death (SCD) (Turakhia et al. in Eur Heart J 39:2314-2325, 2018). In addition to the fact that patients on haemodialysis have a high prevalence of underlying cardiac disease, the stress of haemodialysis itself might also contribute to increased rates of arrhythmias and SCD (Samanta et al. in Can J Cardiol 35:1228-1240, 2019). Methods A Holter 24-h electrocardiogram was set up immediately before the start of haemodialysis for 72 haemodialysis patients (dialysis vintage: 6-8734 days) to record premature ventricular contractions (PVCs) as a marker of arrhythmogenesis for 24 h. Blood samples were also collected every hour during haemodialysis treatment. Each patient was dialyzed against a dialysate consisting of Na.sup.+140 mEq/L, K.sup.+ 2.0 mEq/L, Ca.sup.+ 3.0 mEq/L, Mg.sup.2+ 1.0 mEq/L, Cl.sup.- 110 mEq/L, CH.sub.3COO.sup.- 8 mmol/L and HCO.sub.3.sup.- 30 mEq/L. Results The frequency of PVCs significantly increased in the 4th (80 [+ or -] 34 beats/hour, mean [+ or -] S.E.), 5th (79 [+ or -] 31 beats/hour) and 6th (105 [+ or -] 36 beats/hour) hours (F = 5.24, p < 0.00001, n = 72). The lowest left ventricular ejection fraction (LVEF, p = 0.001) and the highest b-type natriuretic peptide (BNP) levels (p = 0.049) were found in patients with the highest PVC counts. There was an association of positive changes in both serum K.sup.+ ([beta] [+ or -] S.E., 9.7 [+ or -] 2.4, p = 0.0002), Mg.sup.2+ (43.2 [+ or -] 10.3, p = 0.0001) and HCO.sub.3.sup.- (5.3 [+ or -] 1.8, p = 0.005) with the frequency of PVCs for 4 h immediately after dialysis. During the same period, there was an association of lower serum K.sup.+ (- 8.37 [+ or -] 2.16, p = 0.0003) and higher Ca.sup.2+ (73.4 [+ or -] 18.0, p = 0.0002) with the frequency of PVCs. Conclusions Haemodialysis stimulated PVC generation, and this effect was especially prominent during the period immediately after haemodialysis. Some serum electrolyte changes affected this PVC stimulation. A positive change in serum K.sup.+ or Mg.sup.2+ and a negative change in serum Ca.sup.2+ during dialysis are risk factors for stimulating PVCs, particularly in patients with lower serum K.sup.+ or higher serum Ca.sup.2+ levels at the start of dialysis. Keywords: Haemodialysis, Premature ventricular contraction, Potassium, Calcium, Magnesi