中文摘要：

目的：探讨右心室心尖部起搏对Beagle犬心室肌电重构及细胞外信号调节激酶（ERK）1/2磷酸化水平的影响。方法成年雄性Beagle犬12只，年龄3~4年，体重20~24kg，随机分为对照组（n=6）和起搏组（n=6），均植入DDD起搏器后程控至关闭状态，起搏组术后1周时开启起搏器并使心室起搏最大化。于术前及术后1周、4周关闭起搏器后行心电图及超声心动描记术检查，术后4周时处死动物，观察心肌病理结果，采用免疫印迹法检测犬右心室心肌总ERK1/2及其磷酸化水平的变化。结果两组心室肌病理及超声心动描记术、心率、QRS时间、总ERK1/2的表达差异均无统计学意义（均P＞0.05）；与对照组相比，术后4周时起搏组Tp- e间期、Q- T间期均增大，p- ERK增多（均P＜0.05）。结论右心室心尖部起搏可以导致心肌复极延长及促进心肌ERK1/2的磷酸化。

英文摘要：

Objective To investigate the effects of right ventricular apical pacing on electrical remodeling and ERK1/2 phosphorylation in beagle myocardium. Methods 12 male beagles, 3- 4 years old, underwent DDD pacemaker implanta-tion and were randomly divided into two groups （n=6）. The pacemakers were turned on and programmed to ensure ventric-ular pacing 1 week after implantation in pacing group and turned off al the time in control group. The ECG and UCG were recorded before, 1 and 4 weeks after procedure with the pacemaker turned off. The beagles were sacrificed 4 weeks after procedure and phosphorylated ERK1 / 2 of right ventricular myocardium was determined by Western blotting. Results There was no statistical difference in the expression of ERK1 / 2, heart rate, QRS duration, BNP, ventricular myocardial pathology and parameters of UCG between the two groups. Tpeak- Tend interval and QT duration were prolonged and the expression of phosphorylated ERK1/2 increased in pacing group compared with control group（P〈0.05） 4 weeks after pro-cedure. Conclusion Right ventricular apical pacing may induce myocardial repolarization prolongation and promote ERK1/2 phosphorylation of myocardium.