Different influence of peri-atrial epicardial fat on atrial fibrillation recurrence post-ablation: non-obese youth vs. elderly

Peri-atrial epicardial adipose tissue (EAT) actively participates in the initiation and perpetuation of atrial fibrillation (AF). The comparison of prognostic prediction significance of EAT in non-obese (body mass index < 30 kg/m 2 ) young (age ≤ 50) and elderly AF patients remains unclear. This study aims to elucidate the differential predictive impact of EAT on ablation outcomes in non-obese young adult AF patients compared with matched elderly AF cohorts. This 1:2 propensity-matched study included 76 non-obese young AF patients and 152 elderly controls undergoing robotic magnetic navigation-guided ablation. EAT volume and density were quantified via contrast-enhanced cardiac CT. Patients were followed for at least 12 months to document arrhythmia recurrence. No significant difference existed in 1-year AF-free survival between youth (81.6%) and elderly (78.3%, log-rank P = 0.90). Young patients exhibited greater left atrial (LA) volume than the matched elderly (25.8 ± 12.0 vs. 22.6 ± 10.8 cm³, P = 0.046). Multiple cox regression analysis identified higher LA-EAT volume/body surface area (BSA) ratio (OR:1.40; CI:1.05–1.88; P = 0.02) was associated with the AF recurrence in youth. Receiver operating characteristic (ROC) analysis determined that an LA-EAT volume/BSA > 13.994 cm 3 /m 2 predicted youth recurrence with 85.7% sensitivity and 74.2% specificity. These findings suggest a potential association between LA-EAT/BSA and AF recurrence in non-obese youth, supporting its potential role as a risk stratification tool in this population. Further prospective studies with larger cohorts are warranted to validate these findings and to explore whether LA-EAT assessment can inform individualized management strategies. AF = atrial fibrillation; LA-EAT = EAT surrounding the left atrium; BMI = body mass index; BSA = body surface area.