ABSTRACT
Objective To investigate about establishment the animal model of atrial fibrillation(AF) by high thyroxine and electrophysiological study of left atrium.Methods 49 rabbits were randomly divided into three groups, control group (10, injection of saline), withdrawal group (20, injection of levo-thyroxine 50μg/kg, change to inject isodose saline after two months), continuous dosing group (19, injection of levo-thyroxine 50μg/kg everyday).the data of left atrium effective refractory period(AERP), conduction velocity(CV), wavelength(WL) and AF induced ratio were collected after four months.Results The withdrawal group and continuous dosing group AERP200, AERP150 were more shorter than the control group after two months(P<0.05), The continuous dosing group AERP200, AERP150 was shorter significantly than withdrawal group and control group after four months ( P<0.01 ).The withdrawal group and continuous dosing group CV were slower than control group after two months ( P<0.05 ).The continuous dosing group CV was slower significantly than withdrawal group and control group after four months ( P<0.01 ).The withdrawal group and continuous dosing group WL were shorter than control group after two months(P<0.05), The continuous dosing group WL was shorter significantly than withdrawal group and control group after four months (P<0.01).The AF induced ratio in the continuous dosing group increased significantly(P<0.01). After four months, but the withdrawal group decreased, the control group did not induce AF.Conclusion It's feasible to establish the rabbit model of AF by high thyroxine, with left atrium electrophysiological changes, which provides animal model for further to study the pathogenesis of AF cause of hyperthyroidism.