心外膜左心耳起搏建立山羊心房颤动模型

The establishment of atrial fibrillation model in goats with rapid left atrial appendage epicardium pacing

目的探讨开胸置入高频起搏器建立山羊心房颤动(AF)模型的方法和可行性。方法山羊12只,随机分为实验组(6只)与对照组(6只)。开胸后于左心耳底部置入起搏电极,以400±10次/分连续起搏12周,诱导AF。记录山羊体表心电图变化。连续起搏12周采用光学显微镜、电镜观察左、右房游离壁心肌组织学、超微结构的变化。结果1只山羊术中死亡;5只经连续起搏12周后,出现AF心电图改变。左房游离壁较右房游离壁心肌细胞直径变细;左房游离壁较右房游离壁心肌纤维排列紊乱,润盘受损,心肌纤维溶解明显,线粒体增多、体积变大,内质网模糊、有的出现空泡样等改变更加明显。正常对照组左、右房心肌纤维排列规整。结论心外膜左心耳起搏建立AF动物模型是可靠而易行的方法。

Objective To explore the feasibility to establish atrial fibrillation （AF） model via open-chest implantation of high-frequency pacemaker in goats. Methods 12 goats were randomly assigned into trial group （ n = 6） and control group（ n = 6）. Goats in trial group received continuous pacing in the left atrial appendage with 400 ± 10 times/min for 12 weeks. Surface ECG was recorded every week. Light microscope and electromicroscope were used to observe the alterations of the histology and the ultrastructure of the tissue from left and right atrial free wall. Results One goat died during operation. With continuous pacing for 12 weeks, AF ECG appeared spontaneously in all goats, AF was persistent in 3 goats, and it was paroxysmal in 2 goats. Light microscope showed that smaller diameter of myofibrils in the left free wall than right atrial free wall, electromicroscope showed that the intercalated disks were disrupted in some areas, and the sarcomeres were at various stages of contraction, the mitochondria were greatly increased in number and size, and the sarcoplasmic reticulum was partially destroyed and indistinct, these alterations were more parent in left free wall than right one. Conclusion To establish AF model via open-chest implantation of high-frequency pacemaker in goats is feasible and reliable.