title: Clinical Benefit of Ablating Localized Sources for Human Atrial Fibrillation: The Indiana University FIRM Registry.
abstract: BACKGROUND
  Mounting evidence shows that localized sources maintain atrial fibrillation (AF). However, it is unclear in unselected "real-world" patients if sources drive persistent atrial fibrillation (PeAF), long-standing persistent atrial fibrillation (LPeAF), or paroxysmal atrial fibrillation (PAF); if right atrial sites are important; and what the long-term success of source ablation is.
  
  
  OBJECTIVE
  The aim of this study was to analyze the role of rotors and focal sources in a large academic registry of consecutive patients undergoing source mapping for AF.
  
  
  METHODS
  One hundred seventy consecutive patients (mean age 59 ± 12 years, 79% men) with PAF (37%), PeAF (31%), or LPeAF (32%). Of these, 73 (43%) had undergone at least 1 prior ablation attempt (mean 1.9 ± 0.8; range: 1 to 4). Focal impulse and rotor modulation (FIRM) with an endocardial basket catheter was used in all cases.
  
  
  RESULTS
  FIRM analysis revealed sources in the right atrium in 85% of patients (1.8 ± 1.3) and in the left atrium in 90% of patients (2.0 ± 1.3). FIRM ablation terminated AF to sinus rhythm or atrial flutter or tachycardia in 59% (PAF), 37% (PeAF), and 19% (LPeAF) of patients, with 15 of 67 terminations due to right atrial ablation. On follow-up, freedom from AF after a single FIRM procedure for the entire series was 95% (PAF), 83% (PeAF), and 82% (LPeAF) at 1 year and freedom from all atrial arrhythmias was 77% (PAF), 75% (PeAF), and 57% (LPeAF).
  
  
  CONCLUSIONS
  In the Indiana University FIRM registry, FIRM-guided ablation produced high single-procedure success, mostly in patients with nonparoxysmal AF. Data from mapping, acute terminations, and outcomes strongly support the mechanistic role of biatrial rotors and focal sources in maintaining AF in diverse populations. Randomized trials of FIRM-guided ablation and mechanistic studies to determine how rotors form, progress, and regress are needed.
authors.affiliation: Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana. Electronic address: jmiller6@iu.edu.
authors.forename: John M
authors.initials: JM
authors.lastname: Miller
authors.affiliation: Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Vikas
authors.initials: V
authors.lastname: Kalra
authors.affiliation: Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Mithilesh K
authors.initials: MK
authors.lastname: Das
authors.affiliation: Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Rahul
authors.initials: R
authors.lastname: Jain
authors.affiliation: Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Jason B
authors.initials: JB
authors.lastname: Garlie
authors.affiliation: Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Jordan A
authors.initials: JA
authors.lastname: Brewster
authors.affiliation: Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Gopi
authors.initials: G
authors.lastname: Dandamudi
mesh_terms: D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D007196:Indiana; D008297:Male; D008875:Middle Aged; D012042:Registries; D012189:Retrospective Studies; D016896:Treatment Outcome; D014495:Universities / Q000706:statistics & numerical data*
keywords: AF termination; FIRM; ablation; atrial fibrillation; clinical trial; electrical rotors