Pericardial fat is strongly associated with atrial fibrillation after coronary artery bypass graft surgery

Abstract

OBJECTIVES: Recent evidence suggests that pericardial fat may represent an important risk factor for cardiovascular disease because of its unique properties and its proximity to cardiac structures. It has been reported that pericardial fat volume (PFV) is associated with atrial fibrillation (AF). The purpose of this study was to investigate the association between PFV and new-onset AF following coronary artery bypass graft surgery (CABG). METHODS: PFV was measured using computed tomography in 83 patients with coronary artery disease scheduled to undergo elective isolated on-pump CABG. Patient characteristics, medical history and perioperative variables were prospectively collected. Any documented episode of new-onset postoperative AF until discharge was defined as the study end point. RESULTS: Twenty-eight patients (33.7%) developed postoperatively AF during hospital stay. There was no significant difference in demographics and comorbidities among patients that maintained sinus rhythm (SR) and their AF counterparts. In univariate analysis, patients with postoperative AF had significantly more pericardial fat compared with SR patients (195 ± 80 ml vs 126 ± 47 ml, P = 0.0001). Larger left atrial diameter was also associated with postoperative AF (42.4 ± 6.9 mm vs 39.3 ± 4.8 mm, P = 0.017). Additionally, the prebypass use of calcium channel-blocking agents was independently associated with a lower incidence of postoperative AF, confirmed also by multivariate analysis (P = 0.035). In multivariate logistic regression analysis, PFV was the strongest independent variable associated with the development of postoperative AF (odds ratio: 1.018, 95% confidence interval: 1.009-1.027, P = 0.0001). The best discriminant value assessed by receiver operating characteristic analysis was 129.5 ml (sensitivity 86% and specificity 56%). CONCLUSIONS: PFV is strongly associated with AF following CABG, independently of many traditional risk factors. Our findings suggest that PFV may represent a novel risk factor for postoperative AF. However, the role of pericardial fat in AF mechanism needs to be further delineated.