Atrial fibrillation after coronary artery bypass surgery: predictors and the role of MgSO4 replacement.

Background: Supraventricular arrhythmias continue to complicate the postoperative course of patients undergoing myocardial revascularization. The aim of the study was to identify factors associated with atrial fibrillation (AF) and to determine the efficacy of postoperative magnesium sulphate (MgSO4) replacement on the incidence of AF after coronary artery bypass grafting (CABG) operation.

Methods: Fifty patients undergoing CABG were studied prospectively. Consenting patients with good left ventricular function and without any documented arrhythmias were randomly divided into two groups of 25 patients each in a double-blind fashion. The clinical characteristics of both groups were similar. In the study group, 200 mEq MgSO4 was given for the first 5 postoperative days, in the control group, placebo was given instead of MgSO4.

Results: Five (20%) patients in the control group and one (4%) patient in the MgSO4 group experienced AF. There was no significant relationship between the development of AF and the following variables: age; sex; diabetes mellitus; hypertension; previous myocardial infarction; smoking; extension of coronary artery disease; aortic cross-clamp time; number of grafts; cardiopulmonary bypass time; postoperative pericarditis; and anemia.

Conclusion: The use of MgSO4 in early postoperative period is effective in reducing the incidence of AF after CABG in patients with good ventricular function.