摘要目的研究成人心传导系统的Mahaim纤维组织形态学特点并探讨其意义。方法采用自行建立的心脏传导系统检查法，对无心外器官疾病猝死者165例、死于非心脏疾病者760例，作心传导系统的组织学检查，经连续切片确定有Mahaim纤维7例。结果（1）7例具有心传导系统Mahaim纤维，均为束室束型，检出率为0.76％(其中猝死组有5例，占3.0％，非心脏疾病者死亡组中有2例，占0.26％)；(2)Mahaim纤维组织形态学特点是：胞体横径在10～35 μm左右；从房室束分出的Mahaim纤维胞体呈细条状，核居中，而从左束支分出的 Mahaim纤维胞体按其始发点不同自上而下逐渐变大，两种细胞皆胞质丰富，肌原纤维较少， Masson染色淡，与房室束或左束支细胞形态相似，纵切细胞未见分叉，但部分细胞周围见有一薄层结缔组织包围。结论 Mahaim纤维是一种成人房室传导系外的附加传导旁路。

abstractsObjective　 To investigate the Mahaim's fibers of the cardiac con duction system (CCS) of human hearts and study their morphological features. Methods　 The CCS from 165 cases of sudden death without extracardiac causes and tho se from 760 cases of non-cardiac death were sampled using a method established by the authors. Serial sections were prepared for histological observation. Results　 Mahaim's fibers were discovered in 7 cases, 5 cases were in the sudden dea th group, accounting for 3% in that group, 2 cases were in the non-cardiac deat h group, accounting for 0.26% in that group. All cases belonged to the bundle-ve n tricular branch type. The characteristics of Mahaim's fibers were found to be a s follows. Their transverse diameter was 10～35 microns. The bodies of the Mahaim 's fibers that originated from A-V bundle were slender with nucleus in the middle of the cell. While the shape of cells from the left bundle branch varied accord ing to the origin of the Mahaim's fiber with size enlarging from up downward. B oth types of cells showed abundant lightly stained cytoplasm, similar to A-V bu n dle and left bundle branch cells. The cells were not bifurcated and some of them were surrounded by a thin layer of fibrous tissue. Conclusion　 Mahaim's fibers are not a rarity and it is an abnormal development of an A-V by-path.