Magnesium Sulfate Reduces Incidence of Atrial Fibrillation after Coronary Arterial Bypass Surgery: What Is the Proper Dose? A Randomized Trial.

BACKGROUND

Atrial fibrillation (AF) is a common complication after cardiac surgery and impacts length of hospital stay, greater utilization of health care resources, and increases morbidity and mortality. Magnesium sulfate (MgSO4 ) has been well documented in its effect of AF reduction after cardiac surgery especially in coronary artery bypass grafting (CABG) but the dosages are still not settled.

MATERIAL AND METHOD

Eighty-eight elective CABG cases were randomized to receive a high dose (10 gm) or low dose (5 gm) MgSO4 and were blinded into bottle 1 (n = 46) and bottle 2 (n = 42). Patients were closely observed with continuous ECG monitoring in the first 24 hours then observed for clinical symptoms until discharge.

RESULTS

The demographic data were comparable except for a higher body weight in the high dose group (60.21±11.32 kg vs. 65.85±12.2 kg, p = 0.03) and higher incidence of diabetes in high dose group (52.4% vs. 28.3%, p = 0.02). Intraoperative data were similar. No complications were related to MgSO4 except one patient in the high dose group that experienced flushing and abdominal discomfort during administration. Immediate postoperative serum magnesium was higher in the high dose group but rapidly returned to similar level one day postoperatively. AF occurred in nine patients (10.23%), four in the low dose and five in the high dose group and there was no statistical significance (p = 0.62).

CONCLUSION

Current data suggested the safety and effectiveness of MgSO4 for the reduction of the incidence of AF during postoperative CABG surgery. However, there was no statistical difference between the dosages of MgSO4 supplement. The 5-gm-MgSO4 supplement was effective in AF prevention and could avoid the adverse effect from high dose MgSO4 infusion.