Hemodialysis-induced ST-segment deviation

ECGs of 59 patients undergoing hemodialysis (HD): 52% males, age 59±13 years, renal disease duration 9.7±6.7 years, hemodialysis duration 5.2±4.4 years were recorded. Serum electrolytes (potassium-K, sodium-Na, phosphorus-Ph and calcium-Ca), urea and creatinine levels were evaluated before and after HD. ECG analysis on an average P-QRS-T interval in order to avoid accidental events or noise was performed. Pre- and post-HD ECG measurements (mean ± standard deviations) in lead V2 were: ST-dev_pre: 0.13±0.18 mV; ST-dev_post: 0.15±0.22 mV; p=0.03 QRS-ampl_pre: 1.34±0.65□mV; QRS-ampl_post: 1.55±0.79 mV; p<;<;0.001 T-ampl_pre: 0.43±0.31 mV; T-ampl_post: 0.36±0.28 mV; p=0.0016. HD leads to a significant increase in the QRS and decrease of the T-wave amplitude and a considerable shift in the ST-segment. The decrease of the T-wave amplitude and the upward shift of the ST-segment could be explained by potassium decrease during HD. QRS amplitude increase could be explained by the decrease of the extracellular fluid and blood volume and hence a decrease of the cardiac preload.