96-14: Peri-atrial Fat Volume as a Predictor of Outcome in Hybrid Atrial Fibrillation Ablation

Abstract

Introduction: Recently epicardial adipose tissue volume (EAT-V) has been linked to atrial fibrillation (AF) recurrence after catheter ablation. We have explored the relation between periatrial EAT-V and outcome after a hybrid AF ablation (simultaneous epicardial surgical and endocardial catheter ablation). Methods: Fifty patients, 26 paroxysmal (PAF), 22 persistent and 2 long-standing persistent AF (persAF), referred for a hybrid ablation were studied. On preoperative CT-scans, left atrial (LA) and right atrial (RA) EAT-V were quantified with custom-made software (imageJ). EAT was defined as any tissue located directly around the atria within a window of -30 to -190 Hounsfield Units. Also myocardial mass volumes (10 to 120 Hounsfield Units) and LA volumes (LAV) were assessed. Follow-up in 49 patients (1 lost to follow-up) at 1 year was according to the HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of AF. Results: Detailed results are depicted in the Table 1. EAT-V was not significantly different between PAF and persAF patients. EAT-V was not predictive of acute conduction block in the epicardial surgical box lesion. EAT-V neither was predictive of AF recurrence at 1 year. EAT-V in the RA was consistently higher compared to the LA, with significant differences in the PAF (P = 0.009) and persAF groups (P < 0.001). LA EAT-V correlated with LAV determined on CT (r = 0.42, P < 0.01), but not with LAV determined on echocardiography (r = 0.22, P = ns). Overall, LAV determined on CT correlated to but was systematically smaller than LAV determined on echocardiography (r = 0.40, P < 0.01). LA myocardial mass volume positively correlated with LA EAT-V (r = 0.42, P < 0.01). EAT-V = Epicardial Adipose Tissue, LA = Left Atrium, RA = Right Atrium, AF = Atrial Fibrillation, PAF = Paroxysmal AF, persAF = persistent + long-standing persistent AF, SR = Sinus Rhythm. EAT-V = Epicardial Adipose Tissue, LA = Left Atrium, RA = Right Atrium, AF = Atrial Fibrillation, PAF = Paroxysmal AF, persAF = persistent + long-standing persistent AF, SR = Sinus Rhythm. Conclusion: In patients undergoing hybrid AF ablation, total EAT-V is not predictive of recurrence at 1 year. However, LA EAT-V does increase with LAV. As such, fatty infiltration might play a role in early substrate development, and less in AF domestication. Furthermore, acute conduction block of the epicardial box lesion was not influenced by the total amount of left atrial fat.