Abstract 15628: Prevalence of Non-Pulmonary Vein Triggers in Patients With Previous History Of Coronary Artery Bypass Grafting Undergoing Catheter Ablation for Atrial Fibrillation

Abstract

Introduction: Post-operative atrial fibrillation (AF) is reported in up to 5-40% of patients following coronary artery bypass graft (CABG) surgery. Age-related atrial dilatation and fibrosis, electrical remodeling, autonomic imbalance and post-operative inflammation are few of the many pathophysiological factors that play an important role in the genesis and persistence of post-CABG AF. Recent data on fibroblast-myocyte interaction indicates the central role of cardiac fibrosis in the origin of non-pulmonary vein (non-PV) drivers that serve as a source for maintenance of AF. Therefore, we sought to examine the prevalence of non-PV triggers and their impact on ablation outcome in post-CABG AF patients. Methods: Two-hundred sixty seven patients with history of CABG undergoing catheter ablation for atrial fibrillation were included in this analysis (61±11 years, 69% male, LVEF 50±10%, LA size 41.0±6.8mm, non-PAF 72%). All patients underwent pulmonary vein antrum (PVAI) and posterior wall isolation. Non-PV triggers were defined as ectopic triggers originating from sites other than pulmonary veins such as interatrial septum, superior vena cava, left atrial appendage, coronary sinus, ligament of Marshall, crista terminalis. Those were identified by isoproterenol challenge and were ablated based on operator choice. Results: During ablation, non-PV triggers were detected in 243 (91%) patients. The triggers were most commonly mapped to CS (62%) and LAA (70%). Additional sites of non-PV triggers were LA septum, superior vena cave, crista terminalis and mitral valve annulus. Based on operator choice, non-PV triggers were ablated in 118 of the 243 patients and not targeted in 125 patients. At the end of 32±7 month follow-up after a single procedure, overall success rate was 130 (53.5%). Of the 118 patients undergoing non-PV trigger ablation, 81(68.6%) patients remained arrhythmia-free off anti-arrhythmic drugs compared to 49 of 125 (39.2%) where non-PV ablation was not performed (log rank p <0.001, hazard ratio 3.76 [95% CI 2-6.43]). Conclusion: Our results for the first time demonstrate that non-PV foci are highly prevalent in post-CABG AF patients and ablation of those triggers results in significantly better long-term outcome.