title: Use of global atrial fibrillation organization to optimize the success of burst pace termination.
abstract: OBJECTIVE
  The purpose of this study was to determine if burst atrial pacing would have an effect on terminating atrial fibrillation.
  
  
  BACKGROUND
  We hypothesized that frequency domain analysis of a filtered wide bipolar atrial electrogram describes the global organization of atrial fibrillation (AF) and should vary over time. Timing burst pacing to periods of high organization of AF should promote regional atrial conduction block and terminate AF.
  
  
  METHODS
  Nine dogs were conditioned with rapid atrial pacing for 48 h. Electrogram recordings were made from a wide right atrium (RA) to left atrium (LA) bipole and digitally filtered. A fast-Fourier transform was performed every 0.5 s on a sliding 2-s window, and the organization index (OI) was calculated as a ratio of the area of the first four harmonic peaks to the total power of the spectrum. Organization indexes >0.5 indicated more organized AF activity. Right atrium and LA burst pacing (burst) (cycle length 50 ms, 9.9 ms, 9.9 mA, 1 to 4 s) was performed through decapolar catheters. Burst was either random or synchronized to OI >0.5.
  
  
  RESULTS
  Burst termination was attempted 1,814 times (889 OI sync, 925 random) and succeeded in seven of nine dogs. Burst had an overall success rate of 11.1% versus 6.3% for random (p < 0.0003). Biatrial pacing had the highest efficacy for terminating AF, with a success rate of 16.5% for OI sync versus 8.2% for random (p < 0.0001).
  
  
  CONCLUSIONS
  Timing the delivery of the burst pace when the OI is >0.5 increases the efficacy of burst pace termination of AF. Biatrial pacing is more effective than either RA or LA pacing alone.
authors.affiliation: Krannert Institute of Cardiology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Everett
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Akar
authors.forename: Lai-Chow
authors.initials: LC
authors.lastname: Kok
authors.forename: J Randall
authors.initials: JR
authors.lastname: Moorman
authors.forename: David E
authors.initials: DE
authors.lastname: Haines
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial; D004195:Disease Models, Animal; D004285:Dogs; D022062:Electrophysiologic Techniques, Cardiac; D006325:Heart Atria / Q000473:pathology; D008955:Models, Cardiovascular; D016896:Treatment Outcome