Intravenous magnesium sulfate prophylaxis for atrial fibrillation after coronary artery bypass surgery

Atrial fibrillation is a rhythm disorder commonly seen early after coronary artery bypass grafting, and it increases morbidity.

To investigate the effectiveness of magnesium sulfate in the prophylaxis of atrial fibrillation, we conducted a prospective, randomized, placebo-controlled clinical study on 200 consecutive patients in whom we performed elective and initial coronary artery bypass grafting operations. In each group 50% of patients underwent beating-heart operations. In the treatment group 100 patients (76 men and 24 women; mean age, 57.63 +/- 9.68 years) received 24.34 mEq (3 g) of magnesium sulfate in 100 mL of saline solution that was administered over 2 hours (50 mL/h) preoperatively, perioperatively, and at postoperative days 0, 1, 2, and 3. In the control group 100 patients (74 men and 26 women; mean age, 59.96 +/- 9.29 years) received only 100 mL of saline solution according to the same administration schedule as the treatment group.

Atrial fibrillation developed in 15 patients from the treatment group and in 16 patients from the control group. The arrhythmia developed after 37.87 +/- 12.76 and 45.26 +/- 15.27 hours in the treatment and control groups, respectively. Although a significant relationship was found between low magnesium sulfate levels and increased incidence of atrial fibrillation (P <.05), when the incidence of postoperative atrial fibrillation is concerned, no significant difference was found between the 2 groups (P >.05). Also, no significant difference was found between operations with cardiopulmonary bypass and beating-heart operations in terms of atrial fibrillation incidence (P >.05). However, atrial fibrillation extended the duration of hospital stay in both groups (P <.05).

Our findings indicate that magnesium sulfate infusion alone is not sufficient for the prophylaxis of atrial fibrillation.