Volume of Coronary Artery Bypass Surgery and Risk of Postoperative Atrial Fibrillation

PURPOSE: To identify prevalence of atrial fibrillation (AF) in dependence of volume of coronary artery bypass grafting (CABG) as assessed by the number of grafts. MATERIAL AND METHODS: The study included 431 patients with ischemic heart disease (IHD) who underwent CABG. Group 1 comprised patients with single-vessel bypass graft (n=47, 78.7% men, mean age 59.6+/-5.6 years), group 2 - with multivessel bypass grafts (n=384, 76.8% men, mean age 61.0+/-8,1 years). During the observation period postoperative AF developed in 3 patients (6.4%) with single vessel bypass graft and 69 patients (18.0%) with multivessel bypass grafts. At multivariate analysis predictive values were significant for the following parameters: aortic cross-clamping time >36 min - 1.7 (95% confidence interval [CI], 1.1-3.2, p=0.03), ischemia time >19 min - 2.0 (95% CI, 1.1-3.7, p=0.02), age >59 years - 2.4 (95% CI, 1.3-4.4, p=0.005), left atrial dimension >39 mm - 3.7 (95% CI, 2.1-6.6, p<0.0001), left ventricular ejection fraction <51% - 1.9 (95% CI, 1.3- 3.3, p=0.04). Predictive value of cardiopulmonary bypass time >56 min 1.2 (95% CI, 0.56-2.8) was not significant (p=0.5). CONCLUSION: In our study AF in the early postoperative period more often occurred in patients who underwent multivessel coronary bypass surgery. The most powerful predictor of AF in these patients was left atrial dimension exceeding 39 mm.