title: Role of progressive widening of the temporal excitable gap for perpetuation of atrial fibrillation in the goat.
abstract: BACKGROUND
  Previous studies suggest that a short temporal excitable gap exists between the fibrillation waves during atrial fibrillation (AF). The aim of this study was to investigate the role of that gap in the development of sustained AF in goats.
  
  
  RESULTS
  Eight female goats were instrumented with left atrium (LA) electrodes, and sustained AF (>24 h) was induced by intermittent rapid atrial pacing for 9.3+/-4.6 days. In the process of sustained AF development, the atrial effective refractory period (AERP), refractory period during AF (RP(AF)), mean AF cycle length (AFCL), temporal excitable gap during AF (EG(AF) = AFCL - RP(AF)) and degree of fractionation of fibrillation electrograms at LA were studied. When the induced AF lasted for 3-10 min, AFCL, RP(AF) and EG(AF) were 98.3+/-11.0 ms, 90.5+/-13.2 ms and 7.8+/-2.4 ms, respectively. During sustained AF, the values were 84.9+/-5.2 ms, 63.0+/-4.8 ms and 21.9+/-3.5 ms, respectively (P<0.05). Percentage of single potentials was 94.2+/-3.9% and 75.6+/-5.5%, respectively (P<0.05).
  
  
  CONCLUSIONS
  In this model progressive shortening of atrial refractoriness and widening of the temporal excitable gap induced by electrical remodeling created an electrophysiologic substrate for the perpetuation of AF.
authors.affiliation: Department of Cardiology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Zhaoliang
authors.initials: Z
authors.lastname: Shan
authors.forename: Junjin
authors.initials: J
authors.lastname: Yan
authors.forename: Junyan
authors.initials: J
authors.lastname: Zhou
authors.forename: Xiangmin
authors.initials: X
authors.lastname: Shi
authors.forename: Jianping
authors.initials: J
authors.lastname: Guo
authors.forename: Hongtao
authors.initials: H
authors.lastname: Yuan
authors.forename: Maurits A
authors.initials: MA
authors.lastname: Allessie
authors.forename: Yutang
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial; D004195:Disease Models, Animal; D004562:Electrocardiography; D004567:Electrodes, Implanted; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods; D055724:Electrophysiological Phenomena / Q000502:physiology*; D005260:Female; D006041:Goats; D006329:Heart Conduction System / Q000503:physiopathology; D013997:Time Factors