Abstract 14297: Spatially Synchronized Electrogram Islands Within Atrial Fibrillation Predict Termination by Ablation

Abstract

Introduction: It is unclear how persistent atrial fibrillation (AF) terminates by any spatial arrangement of ablation lesions. Hypothesis: We hypothesized that AF that exhibits spatial organization with islands of 1:1 synchronized electrograms within the disordered milieu and, specifically, that patients with larger area islands may be more likely to terminate than those without. Methods: We recruited n=60 patients (72% male, age 63±10 years) in whom AF terminated by ablation (n=30; “Term”) or did not (n=30, “Non-term”). Unipolar AF electrograms were recorded by 64-pole basket catheters in both atria. For all possible 2X2 electrode grids, synchronization was assessed by correlation (repeating shapes + relative timings, coefficient, Fig A). Ablation targeted organized sites (rotational/ focal), then pulmonary vein isolation. Results: Fig A shows (top) AF EGMs in a Term patient showing 1:1 patterns at D2-D3-E2-E3 over time (correlation>0.9). For the entire left atrium, there was a large synchronized island >25% of mapped atria (Fig B, red). Bottom panels show less synchronization in a Non-term patient (Fig A), with <5% area (Fig B). For all patients, synchronized islands (with correlation >0.8) were larger for Term (black) than Non-term (gray) patients over a range of time durations (Fig C, p<0.01 ANOVA). Area of synchronized regions predicted AF termination with c-statistic 0.68, and the optimum cut-point provided sensitivity 87% (specificity 43%). Conclusions: Persistent AF shows organized islands of synchronized electrograms, whose size and duration predict the likelihood of termination by ablation. Future studies should investigate the pathophysiology of synchronized islands in AF.