Predictors of new-onset atrial fibrillation in elderly patients with coronary artery disease after coronary artery bypass graft

OBJECTIVE: To identify the factors associated with the development of postoperative atrial fibrillation (POAF) after coronary artery bypass graft (CABG) in elderly patients with coronary artery disease (CAD). METHODS: A total of 81 patients with CAD who underwent CABG were enrolled in the study. Patients were divided into two groups: Group 1, without postoperative atrial fibrillation (59 patients, 74.6% men, mean age 65.8 ± 4.0 years); Group 2, with early new-onset atrial fibrillation after CABG (22 patients, 90.9% men, mean age 67.7 ± 5.4 years). Interleukin (IL)-6, IL-8, IL-10, C-reactive protein (CRP), fibrinogen, superoxide dismutase (SOD), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and troponin I were studied. RESULTS: During the observation period, atrial fibrillation occurred in 27.2% cases, an average of 4.9 ± 3.8 days after surgery. In group 2, the left atrium (LA) dimension was larger than in group 1 (43.9 ± 3.4 mm vs. 37.6 ± 3.9 mm, P < 0.001). Patients with POAF had significantly higher IL-6 (72.7 ± 60.8 pg/mL vs. 38.0 ± 34.6 pg/mL, P = 0.04), IL-8 (11.9 ± 6.0 pg/mL vs. 7.7 ± 5.4 pg/mL, P = 0.01) and SOD (2462.0 ± 2029.3 units/g vs. 1515.0 ± 1292.9 units/g, P = 0.04) compared with group without POAF. The multivariate analysis showed that the odds ratio (OR) for POAF development in patients with left atrium more than 39 mm was 2.1 [95% confidence interval (CI): 1.2−3.8, P = 0.0004], IL-6 levels more than 65.18 pg/mL—1.4 (95% CI: 1.1−2.7, P = 0.009), IL-8 levels more than 9.67 pg/mL—1.2 (95% CI: 1.1−3.7, P = 0.009), SOD more than 2948 units/g—1.1 (95% CI: 1.01−2.9, P = 0.04). CONCLUSIONS: In our study, the independent predictors of postoperative atrial fibrillation after CABG in elderly patients were left atrium dimension and the increased postoperative concentration of IL-6, IL-8 and superoxide dismutase.