Risk factors of postoperative atrial fibrillation after cardiac surgery

Postoperative atrial fibrillation (AF) occurs in up to 50% of cardiac surgery patients and represents the most common postoperative arrhythmic complication. The etiology of AF after open-heart surgery is incompletely understood and its prevention remains suboptimal. Identification of patients vulnerable for postoperative AF would allow targeting of those most likely to benefit from aggressive prophylactic intervention. The aim of the present study was to evaluate clinical predictors of postoperative AF.

Patients undergoing elective cardiac surgery in the absence of significant left ventricular dysfunction (n = 253; average age 65 +/- 11 years) were recruited to the present prospective study. Ninety-nine patients (39.1%) of the total study population developed AF during the postoperative period. The median age for patients with postoperative AF was 69 years compared with 64 years for patients without (p < 0.001). In addition to advanced age, AF patients were more likely to have surgery for valvular heart disease and less likely to have preoperative beta-adrenergic blockers than patients without AF. Multivariate logistic regression analysis (odds ratio, +/-95% CI, p value) was used to identify the following independent clinical predictors of postoperative AF: increasing age (above vs. below median [OR = 2.6; CI, 1.2 to 3.9; p < 0.01]), and surgery for valvular heart disease (vs. coronary artery bypass grafting [OR 2.8; CI, 1.1 to 3.5; p < 0.01)]). Additionally, postoperative complications (stroke, infections, unstable hemodynamics [OR = 1.9; CI, 1.0 to 7.5; p < 0.05]), and preoperative nonuse of beta-adrenergic blockers (OR = 1.7; CI, 1.1 to 4.9; p < 0.05) were associated with increased risk for postoperative AF. Both, patients with and without AF had similar body mass index, preoperative heart rate, preoperative blood pressure, and duration of surgery. Male sex did not identify patients at high risk for development of AF after cardiac surgery.

Postoperative AF remains the most common complication after cardiac surgery. A combination of advanced age and type of surgery identifies patients at high risk for development of AF after cardiac surgery.