Magnesium sulfate for prevention of postoperative atrial fibrillation in patients undergoing coronary artery bypass grafting

Abstract

The effects of i.v. magnesium sulfate on the frequency of postoperative atrial fibrillation (AF) in patients undergoing coronary artery bypass grafting (CABG) and on the frequency of AF at hospital discharge were studied. The effect of postoperative AF on hospital length of stay (LOS) was also assessed. A retrospective chart review was performed for all patients who underwent CABG surgery by a single surgeon during 2000-2001 at a community medical center. Patients were eligible for inclusion if they had first-time CABG surgery. Patients who underwent CABG surgery in 2000 did not receive magnesium sulfate and served as controls for the study. Patients were included in the magnesium group if they received 2 g of i.v. magnesium sulfate intraoperatively and 2 g every 12 hours postoperatively for at least two consecutive days. A total of 262 patients underwent CABG during the study period, and 28 were excluded from the study. Of the remaining 234 patients, 99 were in the magnesium group, and 135 were in the control group. No significant differences were found between the study groups in recorded demographic characteristics. Postoperative AF occurred significantly less frequently in the magnesium group (p = 0.038). There was no significant difference between treatment groups in the number of patients discharged in AF (p = 0.307). Among all patients, those with AF were significantly more likely to have a prolonged LOS (p = 0.036). CABG patients who received intraoperative and postoperative i.v. magnesium sulfate had a significantly lower rate of AF compared with patients who did not receive the drug. The number of patients discharged with AF was not affected by magnesium administration. AF was associated with a higher likelihood of prolonged postoperative hospitalization.