Abstract
Introduction: It has recently been shown that localized sources (electrical rotors or focal beats) may sustain human atrial fibrillation (AF). We hypothesized that human AF sources show limited migration, unlike animal models in which sources migrate, near regions of fractionated electrograms (CFAE). Methods: In 26 AF patients (63±10 years; 16 persistent), we recorded AF with 64 pole baskets in both atria, then applied the Hilbert Transform. Rotor cores were tracked over time to define migration loci, that we compared to maps of CFAE scored per Scherr et al. (Heart Rhythm, 2007). Targeted ablation (Focal Impulse and Rotor Modulation, FIRM for <10 minutes) was applied at migration loci, to achieve AF termination or 10% slowing (proving the mechanistic role of sources). Results: All patients exhibited AF sources (mean 2.1±0.7; 36 rotors/19 focal beats). Sources migrated within constrained loci in persistent (area 2.5±1.5 cm2) and paroxysmal (2.2±1.0 cm2; p=NS) AF. Notably, migration loci lay near CFAE (p<0.01), but in a patient-specific (adjacent or overlapping) fashion. FIRM terminated or slowed AF (by 16±7%) in 24/26 patients. Conclusions: Localized sources (rotors or focal impulses) that sustain human AF are spatially stable. Although source migration was spatially related to CFAE, CFAE locations per se poorly predicted sources. Brief FIRM ablation (5–10 minutes) at sources terminated/slowed AF in nearly all patients.
