Work

Substrate Comprising Fibrosis and Epicardial Adipose Tissue-Associated Electrophysiological Remodeling Can Sustain Atrial Fibrillation Drivers: Insights from Image-Personalized Computational Simulations

Year: 2026

Type: article

Abstract: BACKGROUND: Computational models of atrial fibrillation help clarify arrhythmia mechanisms, but the contribution of left atrial (LA) epicardial adipose tissue (EAT) is seldom included. OBJECTIVE: To assess whether incorporating EAT-associated effects into fibrosis-based atrial models alters reentrant arrhythmia inducibility and to characterize the pro-arrhythmic properties of EAT-affected tissue. METHODS: by 50%, and conduction velocity by 25%. RESULTS: Sustained reentry occurred in 370 simulations (43.3%), of which 306 had a functional (rotor-driven) component. Functional reentry inducibility rose from 22.8% (fibrosis only) to 41.4% (half-EAT) and 43.2% (full-EAT). At least 1 functional reentry was inducible in 12 of 19 fibrosis-only models, 18 of 19 half-EAT models, and 19 of 19 full-EAT models. The median number of inducible simulations per patient increased from 4 to 6 (P = .004) and 7 (P = .003), without a significant difference between half- and full-EAT (P = .895). Fibrosis-EAT overlap regions comprised only 2.1% of the LA wall but were the most arrhythmogenic, with a median of 65.5% of their volume harboring reentry vs 8.8% (nonsubstrate), 37.3% (fibrosis), and 42.8% (EAT) (all P < .001). In an exploratory analysis of patients undergoing pulmonary vein isolation-only ablation (n = 13), fibrosis-EAT overlap outside the pulmonary vein isolation region was associated with 1-year recurrence (log-rank P = .007). CONCLUSION: Adding EAT effects to fibrosis-based models increased sustained functional reentry, with transmural depth contributing only modestly. Reentry anchored preferentially where fibrosis and EAT effects coexisted.

Source: Heart Rhythm

DOI: 10.1016/j.hrthm.2026.09.057