Objective To observe the morphologic characteristics of myocardial sleeve in sheep~(, ) s pulmonary veins to provide data for the model of ectopic atrial fibrillation.
目的观察山羊肺静脉心肌袖的形态特征，为异位房颤动物模型提供形态资料。
2
The Series 200 engines were a ball bearing designs whereas the earlier Series 100's were plain sleeve bearing engines.