High epicardial fat volume is associated with atrial fibrillation recurrences after catheter ablation

Abstract

Abstract Background Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation therapy for atrial fibrillation (AF). However, even with important technological improvements, AF recurrences are common in long-term follow-up. Recently, epicardial fat tissue (EFT) has been proposed as a potential AF modulator promoting and sustaining atrial arrhythmogenic milieu. Aim In this retrospective single-centre study, we sought to evaluate the association between CT-quantified EFT volume and long-term primary PVI outcome assed by means of continuous ECG monitoring with implantable loop recorders (ILR) in paroxysmal AF patients. Methods A cohort of 92 patients (median age 60.2 [IQR 51.9–64.0]; 74% male) with paroxysmal AF (a single persistent AF episode was accepted) undergoing catheter ablation targeted at PVI was analysed. Prior to CA all patients underwent cardiac CT imaging with subsequent implantation of implantable loop recorder (ILR). Radiofrequency CA ablation with electro-anatomical mapping for PVI was used in 79 patients, balloon cryoablation was used in 13 patients. Verified complete PVI was defined as procedural endpoint. EFT volume was semi-automatically segmented and quantified on contrast enhanced CT studies. AF recurrence, defined as AF burden >0.1% after the blanking period (90 days), was continuously assessed by ILR. Kaplan-Meier analysis of AF recurrence-free survival at 1-year, 2-year and 3-year follow-up periods compared patients stratified into EFT volume tertiles. Results During a median follow-up of 52.6 months [IQR 43–64], AF recurrence was detected in 58 (63%) patients, 29 (50%) of them underwent a repeat ablation. Patients in high, mid, and low total EFT volume tertiles had a median time to late AF recurrence of 154, 373, and 284 days (Fig. 1A). At a 1-year follow-up, patients in the high EFT volume tertile had the worst AF ablation outcome (p=0.023). However, this difference gradually faded-out and became non-significant at 2 and 3 years. ROC analysis revealed an EFT of 95 ml as an optimal cut-off (p=0.002) for expected arrhythmia recurrence post acutely successful PVI (Fig. 1B). Conclusion EFT volume quantification in a relatively homogenous, continuously monitored cohort of patients undergoing catheter ablation for paroxysmal AF revealed a significant association between AF recurrence at 1 year post ablation and volume of epicardial fat. These results suggest a possible role of epicardial adipose tissue as an adverse pro-fibrillatory factor. Identified EFT volume cut-offs have to be validated prospectively on a larger and balanced patient population. Funding Acknowledgement Type of funding sources: None.