犬房室交界区形态结构观察及其临床意义

Morphologic Observation of Canine's Atrioventricular Nodal Junction and Its Clinical Significance

为探讨形成房室结双径路 (DAVNP)的形态学基础。本实验选用 10只犬 ,电生理检查验证DAVNP现象后进行房室交界区的组织学观察。结果显示 :① 10只犬中 2只具有DAVNP现象 ,其中 1例有心房回波。②心房扩展部由三条形态明确的主要由过渡细胞构成的过渡细胞束与房室结 (AVN)相连 ,三条过渡细胞束自左上向右下依次走行于不同的层面。左过渡细胞束位置偏左上 ,自左侧心房肌向前下沿室间隔肌上缘向右至AVN左后端 ;中过渡细胞束位置略低 ,自冠状静脉窦 (CS)壁向前沿锥形间隙或室间隔肌与右房肌之间至AVN后端 ;右过渡细胞束位置偏右下 ,自三尖瓣与CS口 (CSO)之间及CSO周围向前沿心内膜下至AVN右后端甚至浅层 ,部分与浅层纤维自然延续。其中右、中过渡细胞束在靠近AVN时基本汇合一处。三条过渡细胞束纤维纤细 ,排列疏松、染色浅淡 ,左过渡细胞束纤维数量相对较多。③AVN分深、浅两层 ,深层纤维排列致密、方向较乱且交织成网 ,染色较深 ;浅层纤维排列疏松且较平行 ,由后向前走行 ,染色相对浅淡 ,位于AVN右表面。④ 1例DAVNP犬AVN明显稀疏、细胞分散、染色浅淡且相对均匀。此例犬CSO及CS腔明显增大 ,CS与AVN距离明显缩短。⑤右房后壁可见排列较密集、染色浅淡的过渡细胞。结果提示 :犬房室交界区不同部位形态结构有?

The purpose of the study was to observe the morphology basis underlying dual atrioventricular nodal pathways (DAVNP).After the electrophysiologyic examination was performed in ten canines,the atrioventricular junction (AVJ) was used to examine the histologic features by serial sections.In ten canines,discontinuous atrioventricular conduction curves was testified in two canines,including atrioventricular node (AVN) echoes in a canine.Three morphologically distinct transitional cellular bundles were found to link forward with the AVN respectively from the left atrium,the wall of the coronary sinus,the periphery of the coronary sinus orifics (CSO) and the region between the septal part of the tricuspid value and the CSO.Right and middle transitional cellular bundles converge together near the AVN.The muscular fibers of three transitional cellular bundles were slender and stained light.The AVN consisted of the deep stratum and the superficial stratum.The cells of the deep stratum were tightly packed and stained deep.The cells of the superficial stratum were sparsely packed and relatively stained light with lying on the right surface of the AVN.In a canine with evidence of DAVNP,The AVN was sparsely packed and stained light.The CSO and the sinus intercavarum showed significant enlargement.Otherwise,The transitional cells were also found in the posterior wall of the right atrium.The results suggest that morphologic characteristics are obvious difference in canine's AVJ.Three transitional cellular bundles and the AVN may provide the morphologic basis of DAVNP.Under the specified conditions of physiology and pathology,the electrophysiologic manifestation of DAVNP may possibly occur.