AF Drivers Where Ablation Terminates Persistent AF Fluctuate Due to Competing Drivers but Remain Anchored in Specific Locations

Introduction: Mechanisms for persistent atrial fibrillation (AF) are unclear. We reasoned that AF drivers may fluctuate due to competing drivers in stereotypical spatial locations. This may explain why studies focused on small regions may show disordered waves while global mapping shows organized drivers. Hypothesis: That closely-spaced AF drivers may fluctuate more than drivers that are widely separated by mapping AF globally for prolonged durations using 2 independent mapping methods. Methods: In 55 patients with non-paroxysmal AF (24% female; 62.2±9.7 years), ablation at drivers identified by 64 pole baskets (Abbott, CA) terminated AF before pulmonary vein (PV) isolation. We mapped 360±45 AF cycles using (1) an open source phase method and (2) commercial tools, and quantified both fluctuations and locations of mapped drivers. Results: Patients had 4.2 ± 2.0 potential drivers by non-proprietary mapping (fig A), located per fig B. AF termination sites showed rotational/focal patterns (51/55 vs 55/55 patients; p=0.13 methods 1 vs 2) that fluctuated over time. In space, each AF driver was most prevalent in the left atrium, with clustering near left PVs (p<0.05). Separation between drivers varied non-significantly with fluctuations. Drivers trended to be more stable in LA than RA (χ 2 = 2.11, p=0.12). Conclusions: Potential AF drivers where ablation terminates persistent AF are spatially stable but fluctuate over time. Fluctuations reflected competing sources, trended to be more prevalent in left atrium but were not clearly related to inter-site distance. Studies should examine the functional determinants of AF driver fluctuations.