Factors producing increase of QRS complex amplitude during hemodialysis

: An increase of total amplitudes of QRS complexes induced by the hemodialysis (HD) procedure is a common phenomenon in hemodialysed patients. The aim of the study was to define factors responsible for the growth of QRS complex amplitude as a result of HD. The study was carried out on a group of 48 patients. Before and after HD procedure basic biochemical blood tests were performed and the following parameters calculated for each patient: (a) the total amplitude of QRS complex, (b) the total volume of body water (TBW), the extracellular volume (ECW), and the intracellular volume (ICW), as well as the TBW, ECW and ICW indices standardized against the patient body weight. The levels of albumin, total protein, intact PTH (iPTH), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-alpha) were determined before HD. The rates of Kt/V and normalized protein catabolic rate (nPCR) were calculated. The total amplitude of QRS complexes before HD was 13.09 +/- 3.3 mV and it increased significantly after HD to the value of 17.68 +/- 4.03 mV (p<0.001). An increase of QRS amplitude was observed in 35 patients (72.92%). The results of the study revealed, that the most important factor responsible for the growth of the total amplitude of QRS complexes after HD procedure is the value and changes in the ECW volume. The validation of the correlations disclosed in our study between the increase of the total amplitude of QRS complexes and IL-6 )positive correlation), and the nPCR value (negative correlation) require further studies on large groups of HD patients as well as a retrospective analysis of patients' survival rates.