Abstract 11535: Elimination of Recurrent Atrial Fibrillation by Focal Impulse and Rotor Modulation (FIRM) Alone
Introduction: Atrial fibrillation (AF) may recur in a third or more of patients after pulmonary vein isolation (PVI). We hypothesized that electrical rotors or repetitive focal impulses, localized sources recently demonstrated in human AF, may be sites where targeted ablation (Focal Impulse and Rotor Modulation, FIRM) alone may eliminate recurrent AF.
Methods: In 35 AF patients (63±9 years; LA size 48±7 mm; 24 persistent), we recorded AF at 128 electrodes using basket catheters in both atria. Applying a novel physiological mapping system to identify sources, we performed FIRM ablation directly at AF rotors/focal impulses (endpoint: AF termination or 10 minutes' ablation; repeated for ≤ 3 sources). In Group I, ablation stopped at this point (i.e. no PVI). In Group II, circumferential PVI (CPVI) was then performed after FIRM.
Results: All patients exhibited AF sources, for an average of 2.2±0.9 rotors (n=49) and/or focal beats (n=23). FIRM terminated AF (n=21; within 6.6±5.4 minutes) or greatly slowed AF (n=10; 15±7% CL lengthening) in 89% patients. In group I (n=5; 3 persistent), FIRM terminated AF in 3.3±2.4 minutes (at 3 LA/2 RA sources). In group II (n=29; 21 persistent), FIRM terminated AF in 7.7±5.6 minutes (p=0.11 vs group I) at 13 LA/3 RA sources (p=0.33 vs group I). Fig A shows an LA rotor (B) in mid-posterior LA between prior PVI lesions in a man with persistent AF despite 3 prior procedures. FIRM terminated AF to sinus rhythm in 4.5 minutes. AF was non-inducible and no other ablation was performed. All group I patients and 70% of group II patients are free of AF (p=0.16; at 225±301 days) using implanted monitors (83%).
Conclusions: Localized electrical rotors or focal beats remote from the PVs may cause recurrent AF, e.g. after failed conventional ablation. Targeted ablation at only these sources (FIRM) may rapidly terminate and eliminate AF on rigorous follow-up, substantially reducing ablation and total procedural time.
- © 2011 by American Heart Association, Inc.