[Effects of atrial excitable period on the stability of atrial fibrillation in goats].
OBJECTIVE
To investigate the effects of atrial excitable period (EP) on the stability of atrial fibrillation (AF) in goats.


METHODS
Ten female goats were instrumented with epicardial electrodes patches on the left atrium (LA) free wall. AF was induced and maintained by a home-made stimulator with frequency of 50 Hz at a 1-second duration and a 2-seconds interval. The stimulator was disconnected regularly. AF-induced duration, average AF cycle length (AFCL), and atrial effective refractory period during AF (ERP(AF)) were measured; EP was calculated by AFCL-ERP(AF).


RESULTS
Eight goats were studied. Persistent AF (> 24 h) could be induced in all the 8 goats within 6-16 days. When the induced AF lasted for 3-10 min or 24 h, the AFCL was 98.3 ms +/- 11.0 ms and 84.9 ms +/- 5.2 ms (P < 0.05), respectively, ERP(AF) was 90.5 ms +/- 13.2 ms and 63.0 ms +/- 4.8 ms (P < 0.05), respectively, and EP was 7.8 ms +/- 2.4 ms and 21.9 ms +/- 3.5 ms (P < 0.05), respectively.


CONCLUSIONS
The decrease in ERP(AF) is more significant than the shortening in AFCL, resulting in the gradually widening of EP which may contribute to the perpetuation of AF.
Department of Cardiology, General Hospital of PLA, Beijing 100853, China.
Zhao-liang
ZL
Shan
Yu-tang
YT
Wang
Xiang-min
XM
Shi
Jun-jin
JJ
Yan
Jun-yan
JY
Zhou
Jian-ping
JP
Guo
Wei-hua
WH
Wang
Tian-de
TD
Li
D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology*; D004195:Disease Models, Animal; D004562:Electrocardiography; D005260:Female; D006041:Goats; D006325:Heart Atria / Q000503:physiopathology*