Assessment of corrected QT interval in sickle-cell disease patients who undergo erythroapheresis

Extension of the QT interval is characterized by syncope and cardiac arrest and often occurs in association with medical therapies and procedures. Whether erythroapheresis (EPH) could influence the QT interval duration in patients with sickle cell disease (SCD) is not known. We aimed to investigate the effects of EPH on the heart rate-corrected QT (QTc) interval. The study included 25 patients with SCD who underwent 34 EPH procedures. Two independent observers measured QTc interval duration from electrocardiograms performed continuously for 3 min at three different points during the EPH procedures (prior to EPH, after completion of 50% EPH and 15 min after EPH). Multiple regression analysis was used to determine if the ionized plasma calcium, the level of plasma magnesium, citrate infusion rate and painful crisis significantly contributed to the QTc interval. There was a non-significant trend (P = 0.184) towards increased QTc in sickle cell patients during EPH compared with pre-EPH values. QTc prolongation (>440 ms) occurred in 72% of the procedures. Fifty percent QTc values returned to baseline after the procedure. The independent variables were not significantly associated with QTc interval. Exchange procedures can induce QTc prolongation in patients with SCD.