The impact of liraglutide on epicardial adipose tissue and left atrial remodelling prior to ablation for atrial fibrillation

Introduction Epicardial adipose tissue (EpAT) is an important factor in initiation and persistence of atrial fibrillation, with increasing evidence linking this to poorer outcomes from ablation. While pre-ablation weight loss leads to improved freedom from AF, the mechanism remains elusive. Purpose The aim of this study was to determine whether liraglutide-assisted weight loss reduced EpAT and altered left atrial structure and function using dedicated cardiac magnetic resonance imaging (CMR) in obese AF patients (BMI 30-40) awaiting catheter ablation. Methods This prospective analysis included the first 15 participants from GOAL-AF (NCT-05221229). Following baseline CMR, participants received liraglutide in addition to lifestyle intervention, with repeat imaging ≥120 days later. EpAT quantification utilized standard short-axis cine stacks on 1.5T scanner. Continuous contouring from atrioventricular groove to apex during end-systole generated mass values, converted to volume using standard myocardial density (1.055g/ml). Left atrial volumes employed conventional biplane and stack methodologies. Intra-observer variability was assessed through blinded repeat measurements one month apart. Results Participants (age 62±12 years, 67% female, baseline BMI 35.3±3.3kg/m²) achieved significant weight reduction of 7.4kg (2.7-16.5kg) representing 7% (2-15%) from baseline. All participants tolerated liraglutide therapy with median duration of 126 days (2.6mg daily). EpAT reduced from 83±36ml to 75±32ml (p=0.04). Maximal LA volume decreased significantly by both biplane (59±22 to 53±20ml/m², p=0.01) and stack methods (58±22 to 53±20ml/m², p=0.006). Minimal LA volumes showed comparable reductions (biplane: 35±22 to 30±19ml/m², p=0.04; stacks: 39±22 to 34±20ml/m², p=0.007). Left atrial ejection fraction, and left ventricular parameters remained stable throughout. EpAT measurement reliability proved excellent with intra-observer ICC of 0.90 (95%CI 0.82-0.95) and repeatability coefficient of 13ml. Conclusions This study demonstrated a parallel reduction in both epicardial fat and left atrial volumes, consistent with a mechanistic link between adipose tissue regression and reverse atrial remodelling. Measurement of EpAT is reliable and reproducible using standard cardiac MRI imaging sequences. This approach could transform pre-ablation risk stratification and monitoring, making epicardial fat assessment part of routine clinical practice rather than a research tool. EpAT Measurement