Role of progressive widening of the temporal excitable gap for perpetuation of atrial fibrillation in the goat.
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.
Shan
Zhaoliang
Z
Department of Cardiology, Chinese PLA General Hospital, Beijing, China.
Yan
Junjin
J
Zhou
Junyan
J
Shi
Xiangmin
X
Guo
Jianping
J
Yuan
Hongtao
H
Allessie
Maurits A
MA
Wang
Yutang
Y
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