人心传导系统的变异

目的　探讨划分心传导系统 (CCS)形态变异与发育异常 (畸形 )的界线。　方法　用我们建立的CCS检查法 ,即窦房结和房室结沿其长轴切 1～ 2块 ,房室束沿长轴垂直切 2～ 4块 ,连续切片 ,间断取片 ,每例共取 30片。对 886例 (非心源性死亡 737例 ,心源性猝死 149例 )人CCS进行组织学观察 ,并对两组进行CCS形态、死因分析比较。　结果　 1 人CCS具有大小、位置及形态的先天性变异 ;2 也有增龄性变化的后天性变异 ;3 死因不明的心源性猝死者中CCS见到有成年人胎儿型房室结、房室结全部移位至房室束穿部、房室束穿部完全分成 3束以上、房室束分叉部房室结化及移位至三尖瓣根部等 ,这些改变不应认为是正常变异 ,因为它们都可能有病理学意义。　结论　房室束分叉部向室间隔膜部内移位、偏位于室间隔左侧、向室间隔左下侧移位 ,以及不足 1 2房室结移位至中心纤维体内 (房室束穿部 ) ,心肌束移位于房室束或左束支内等应属CCS变异 ,不是畸形。

THE NORMAL VARIATION OF HUMAN CARDIAC CONDUCTION SYSTEM

Objective To explore the delineation between normal variations and developmental anomalies (malformation) of human cardiac conduction system (CCS). Methods The CCS of 886 cases (737 cases were noncardiac death,149 cases died of sudden cardiac death) were examined histologically using the method designed by the authors that tissues containing the SAN and AVN were cut along the long axes of the nodes in 1-2 block and the HB perpendicular to its long axis 2-4 blocks.The morphology and causes of death in CCS of two groups were also studied. Results 1.There were congenital variations in human CCS with respect to the sizes,position and shape;2.There were postnatal variations in CCS accompanying the aging process;3.It was revealed that there were developmental anomalies in CCS with sudden cardiac death,which included fetal typed atrioventricular node (AVN) in adults, complete displacement of the AVN into the central fibrous body,complete separation of the HB into more than 3 bundles and the displacement of bifurcation of the HB into the root of tricuspid valve.These changes should not be grouped into normal variations,since they are related or potentially related to sudden cardiac deaths.Conclusion The following changes should be included in normal variation or CCS:displacement of the bifurcating portion of the HB into the pars membranacea of the ventricular septum;left sided deviation of downward and leftward displacement of that portion;displacement of less than 1/2 of the AVN in to the central fibrous body;displacement of the myocardium into the HB or LBB.;