Abstract Body: Introduction: Atrial fibrillation (AF) is classified as paroxysmal (PAF), persistent (PEAF), or longstanding persistent (LPAF) based on the duration of episodes, however mechanistic differences are poorly understood. Pulmonary vein isolation (PVI) is the cornerstone of AF ablation. PVs and the posterior wall (PW) of the LA share a common embryologic origin, and PW isolation is often performed for PEAFs and LPAFs. Nevertheless, ablation success is ~80% for PAF but only ~50% for PEAF and LPAF.
Hypothesis: The latest mapping systems perform automated detection of complex fractionated atrial electrograms (CFAEs), which identify key substrate contributing AF perpetuation. We hypothesize that the distribution of CFAEs evolves between AF subtypes, providing novel mechanistic insights.
Aims: To characterize the distribution of CFAEs for each AF subtype.
Methods: 121 patients (83 male, 38 female) referred consecutively (Nov 2024 to Jan 2026) for ablation of PAF (n=47), PEAF (n=40), and LPAF (n=34) were included. 43 (91%) of PAFs presented in sinus rhythm (SR). AF was inducible in 26 (60.4%), allowing for CFAE mapping. 18% of PEAFs presented in SR and AF was inducible, allowing CFAE mapping for all PEAFs and LPAFs.
Results: Total mapping points (OCTARAY™ catheter, CARTO™ 3 platform, J&J MedTech) increased (8606±3083, 11027±4493, 13481±5254) for PAF, PEAF, and LPAF respectively, attributable to a rise in LA volume (129±30 cc, 147±46 cc, 193±44 cc) and fibrosis (<0.05 mV: 2.8%, 14.1%, 23.5%, p<0.01). Both high (34±48, 98±116, 164±161) and low (113±223, 393±420, 567±437) confidence CFAEs also increased from PAF to PEAF and LPAF (p<0.05). CFAEs occurred within the PV antra in 91.2% of PAFs but only 52.1% of PEAFs and 46.8% of LPAFs. The posterior wall accounted for 85.7% of extra-PV CFAEs in PAFs, but only 54.4% and 47.5% for PEAFs and LPAFs. In LPAF, 61.7% of anterior CFAEs were adjacent to the RPVs, where 29% of total CFAEs were found.
Conclusions: The progression from PAF to PEAF and LPAF is accompanied by an increasing burden of CFAEs, with migration away from the PV antra and from posterior to anterior. This indicates increasing mechanistic complexity involving non-PV substrate and the anterior LA. These results suggest that detailed mapping should be performed routinely at the start of AF ablation procedures, with ablation strategy customized to account for regions with greatest mechanistic significance.