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.
ABSTRACT
Objective To investigate the feasibility and methodology of active fixation lead on patients under right ventricular outflow tract septum(RVOTS) pacing.Methods Fifty DDD pacemaker patients were enrolled 31 male,23 female,50~86 years old,mean age 67.7?8.6.Ventricular active fixation lead was implanted in the right ventricular apex(RVA) and RVOTS successively and pacing parameter was tested.Results The success rate of RVOTS active fixation lead implantation was 98.15%.Mean lead threshold was 0.73?0.12 V.Pacing QRS duration show a significant difference between RVOTS pacing and RVA pacing,130.45?18.24 and 153.11?20.10,respectively(P
ABSTRACT
Objective To compare the cardiac function effect of right ventricular septum(RVS) pacing with that of right ventricular apex(RVA) pacing.Methods One hundred and six patients with indication of dual chamber pacemaker implantation were divide into two groups randomly.In each patient,influence of different pacing site to LVEF and pacing parameter were examined and left ventricular eject fractions were compared.Results All patients' operation were successful,LVEF of RVS group compared with that of RVA showed a significant difference.Conclusion The cardiac function are significantly different between right ventricular septum pacing group and right ventricular apex group.