The effect of spironolactone in reducing the risk of postoperative atrial fibrillation in patients undergoing coronary artery bypass graft surgery: randomized single-blind placebo-controlled study.

Background: Postoperative atrial fibrillation (POAF), one of the most common cardiac arrhythmias following coronary artery bypass graft (CABG) surgery is associated with unfavorable outcomes.

Objectives: This study investigated the effect of spironolactone administered two weeks before surgery on the incidence of POAF in patients undergoing CABG.

Methods: This randomized single-blind placebo-controlled study was conducted on 130 CABG patients. All patients were randomly divided into intervention and control groups including 65 cases for each group. In the intervention group, patients received 50 mg of spironolactone orally daily for 2 weeks before surgery, and in the control group patients received placebo daily from 2 weeks before surgery. All patients were continuously monitored for the occurrence of POAF for two weeks postoperatively.

Results: The mean age of the patients in the intervention and control groups was 61.7 ± 5.4 and 60 ± 6.7 years, respectively. The incidence of POAF in the intervention and control groups was 7.7% and 20%, respectively (Odds Ratio = 0.33, P = 0.042). All demographic and clinical variables were similar in patients with and without POAF (all P > 0.05).

Conclusions: Our findings revealed that in comparison to placebo, the use of spironolactone is associated with reduced incidence of POAF in CABG candidates.