Evaluation of Using IV Magnesium Sulfate for Prevention of Postoperative Atrial Fibrillation Arrhythmia in Patients Undergoing Coronary Artery Bypass Grafting

Introduction & Atrial fibrillation (AF) is the most common important arrhythmia of cardiac surgery. Magnesium, like several other pharmacologic agents, has been used in the prophylaxis of postoperative AF with varying degrees of success.The purpose of this study was to determine the effect of magnesium administration in reducing postoperative AF after cardiac surgery. In a double blind randomized clinical trial, over an 18-month period, 162 patients that electively scheduled for coronary artery bypass graft (CABG) surgery involving cardiopulmonary bypass were studied. The patients were randomly assigned to magnesium receiving (n=81) and placebo (n=81) groups. In magnesium group, the patients were received an intravenous infusion of magnesium sulfate, 2 g, immediately after the termination of cardiopulmonary bypass. Total serum magnesium concentration was measured before induction, immediately after operation (before magnesium infusion), and 24 hr after ICU admission. AF was sought with a 12-lead electrocardiogram (ECG) from the end of surgery up till 72 hr after operation. AF occurrence in magnesium group (7.4%) was lower than placebo group (34.6%) and the differences were statistically significant (p<0.0001). There was no significant difference in serum magnesium level during the follow-up. In patients with AF, the serum magnesium concentration before operation was significantly lower than others (p=0.0001). In all patients, the serum magnesium was decreased immediately after operation (p<0.0001). This study showed that hypomagnesemia is a common finding after postoperative cardiac surgery and it is associated with post operation AF. The use of magnesium in early postoperative periods is highly effective in reducing the incidence of AF after coronary artery bypass grafting.