Role of Preexisting Proarrhythmic Atrial Remodeling in Post-Coronary Artery Bypass Grafting Atrial Fibrillation

Introduction Due to its deleterious effects, early identification of patients at risk of postoperative AF (POAF) is of critical importance. Preexisting proarrhythmic atrial remodeling could contribute to this increased risk. Therefore, we aimed to evaluate the presence of preexisting proarrhythmic atrial remodeling and its impact on POAF occurrence in patients undergoing coronary artery bypass grafting (CABG). Methods Data regarding atrial structural (atrial size and histology), electrical (P-wave and atrial action potential parameters, mRNA expression of several AF-related genes), and autonomic (heart rate variability parameters) proarrhythmic remodeling were compared between patients with (AF; n=11) and without (no-AF; n=19) POAF. Impact of POAF on postoperative outcomes was also evaluated. Results No significant difference was observed in atrial electrical parameters between the two groups (all p>0.05). However, compared with no-AF, AF patients had more important subepicardial adipose infiltration (p=0.02) and higher markers of parasympathetic and sympathetic modulation (both p=0.03). Patients with POAF had longer hospital stay and more often presented postoperative renal dysfunction (both p=0.04). Conclusion These findings suggest that preexisting atrial structural (i.e., increased atrial subepicardial adiposity) and autonomic (i.e., sympatho-vagal coactivation) alterations could favor the occurrence of POAF. At its turn, POAF was associated with altered postoperative outcomes in CABG patients.