Hemodialysis-associated cardiac arrhythmias: a lower risk with bicarbonate?

The role of hemodialysis (HD) as an arrhythmogenic event has recently been emphasized. We studied 18 patients by Holter monitoring, comparing the arrhythmogenic effect of acetate dialysis (AHD) and bicarbonate dialysis (BHD). The frequency of ventricular arrhythmias was 93 +/- 66/h in AHD and 32 +/- 26/h in BHD (p less than 0.005). According to the classification of Lown and Graboys, classes III and IV were more often to be found in AHD than in BHD and no patient on BHD was in class IVB and class V. Five patients affected with ischemic heart disease had more frequent and dangerous ventricular arrhythmias than the others; a significant difference between buffers was recorded in all cases but 1. Intradialytic changes in body weight, hematocrit, osmolarity, ionized calcium and potassium during AHD and BHD were similar. The two methods only differed in the quickness and degree of correction of acidosis, and this was related to a significant difference in intraerythrocytic potassium at the end of the session. The quicker and more regular correction of acidosis with BHD and the consequent difference in ionic flows between the intra- and extracellular spaces, as demonstrated by changes in intraerythrocytic potassium at the end of the session, could account for the seemingly less arrhythmogenic effect of BHD.