The efficacy of supplemental magnesium in reducing atrial fibrillation after coronary artery bypass grafting.

Study answer

What this study found

Overall prophylactic magnesium did not significantly reduce postoperative atrial or ventricular arrhythmias after CABG. Total atrial fibrillation occurred in 32 of 105 patients (30.5%) in the magnesium group versus 41 of 97 (42.3%) in control, p=0.08. A benefit was seen only for atrial fibrillation on postoperative day 1, which was lower with magnesium (3/105, 2.9%) than with control (9/97, 9.3%), p=0.05. Urine magnesium and calcium excretion were higher in the magnesium group, but serum magnesium levels were not significantly different after postoperative day 4.

Study & population

Randomized controlled trial in adults undergoing elective isolated coronary artery bypass grafting at a midwestern university medical center over a 5-year period.

Intervention

Magnesium sulfate 80 mg/kg ideal body weight was infused in 100 mL D5W over 30 minutes before cardiopulmonary bypass, followed by a continuous intravenous infusion of 8.0 mg/kg ideal body weight per hour for 48 hours in 100 mL D5W.

Key limitation

The main arrhythmia endpoint was not statistically significant, and the apparent benefit was limited to one early postoperative day.

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Original abstract