Effects of atrial excitable period on the stability of atrial fibrillation in goats
Shan, Z.-l.; Wang, Y.-t.; Shi, X.-m.; Yan, J.-j.; Zhou, J.-y.; Guo, J.-p.; Wang, W.-h.; Li, T.-d.
Zhonghua Xin Xue Guan Bing Za Zhi 33(11): 992-994
2005
ISSN/ISBN: 0253-3758 PMID: 16563244 Document Number: 592913
To investigate the effects of atrial excitable period (EP) on the stability of atrial fibrillation (AF) in goats. 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). 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. 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.