目的　探讨肺静脉起源性房颤的解剖学机制 ,为经肺静脉射频消融治疗阵发性房颤提供应用解剖学资料。　方法　在 38例心标本上观察了肺静脉壁肌层的结构和形态 ,并用组织学和透射电镜等方法确定肺静脉壁外层缠绕肌的来源和性质。　结果　自肺静脉口向远端的肺静脉壁肌层的外层有心房肌缠绕 ,其出现率为87 8% ;心房肌缠绕的形态可分为括约肌型、“U”型和交叉型 ;缠绕肺静脉的心房肌中有一些可能是起博细胞 (P细胞 )。　结论　肺静脉壁肌层的外层有心房肌缠绕 ,其中有一些可能是P细胞。这些结果为阐明房颤发生的机制以及在临床射频消融术中 ,寻找肺静脉口、确定消融的位置和深度等提供了部分解剖学依据 Objective To investigate the anatomic mechanism of pulmonary fibrosis in patients with atrial fibrillation and provide anatomic data for the treatment of paroxysmal atrial fibrillation by pulmonary vein radiofrequency ablation. Methods The structure and morphology of the muscular layer of the pulmonary vein were observed on 38 heart specimens. The origin and the nature of the outer layer of the pulmonary vein were determined by histological and transmission electron microscopy. Results There was atrial fibrillation in the outer layer of the pulmonary vein wall from the pulmonary vein to the distal wall. The incidence of atrial fibrillation was 87.8%. The morphology of atrial fibrillation could be divided into sphincter type, “U” type and cross type. Some atrial muscles may be booster cells (P cells). Conclusion There is atrial fibrillation in the outer layer of pulmonary vein muscle wall, some of them may be P cells. These results provide a partial anatomical basis for elucidating the mechanism of AF and elucidating the location and depth of pulmonary veins during clinical radiofrequency ablation