The Effect of Continuous Magnesium Infusion to Prevent Postoperative Atrial Fibrillation in Patients Undergoing Off-Pump Coronary Artery Bypass Grafting.

Introduction: Postoperative atrial fibrillation (POAF), which occurs in almost 20-40% of cardiac surgeries, is associated with life-threatening complications. Serum hypomagnesemia, a frequent finding after cardiac surgeries, is a predictor for POAF. In this study, we investigated the effect of continuous magnesium infusion to prevent POAF in patients undergoing off-pump coronary artery bypass grafting (OP-CABG).

Materials and methods: A prospective, randomized controlled study was conducted on 110 patients undergoing OP-CABG. Patients were classified into two groups after reaching the intensive care unit (ICU). Group M was started on magnesium (Mg) infusion at 750 mg/h for 3 days after an initial bolus dose of 1.5 g of magnesium sulfate, to target a serum magnesium level of 1.5 to 2 mmol/L. The control group (Group C) did not receive any infusion. The incidence of POAF, magnesium values, duration of ICU stay, number of patients who required pharmacotherapy and cardioversion, and maximum vasoactive-inotropic score (VIS max) were recorded. A P <.05 was taken as statistically significant.

Results: 104 patients were analyzed. The incidence of POAF (19.2% vs 1.9%, P = .008) and the number of patients requiring pharmacotherapy other than magnesium (15.4% vs 1.9%, P = .0310) were significantly higher in group C. Mean of peak magnesium values (1.624 ± 0.136 vs 0.710 ± 0.147, P < .001) was significantly higher in Group M. The number of patients requiring cardioversion (P = .618), duration of ICU stay (P = .121), and the VIS max (P = .360) were not significantly different between groups.

Conclusion: Postoperative continuous magnesium infusion after a bolus was effective in preventing POAF in patients undergoing OP-CABG by maintaining serum magnesium levels (1.5-2 mmol/).