房室交界区的特化心肌纤维构筑

ARCHITECTURE OF THE SPECIALIZED MYOCARDIAL FIBERS OF THE ATRIOVENTRICULAR JUNCTION AREA

本研究用连续切片方法,在光镜下观察了房室交界区特化心肌纤维的构筑。人房室结的后端向后分叉,发出左、右后延伸。房室结可分为浅、深两层。深层又可分出上、下两部。浅层纤维垂直行,在结的前端加入深层。深层下部系结的主轴,纤维纵行,在结的后端加入右后延伸。深层上部的纤维斜行,在结的后端加入左后延伸;在前端并入深层下部。房室束前部的纵行分离比后部明显。束分叉部的左下部延续为左后分支;左上及中间上部为左前分支;右侧及中间下部为右束支。本文就房室交界区内的双路或多路传导途径、纵行分离及折返的形态学依据,进行了讨论。

The architecture of the specialized myocardial fibers of the atrioventricular junction area(AVJ) were observed under microscope on serial sections. It was found that the human A-V node extend backward divergently to form two posterior extensions (left and right, LPE, RPE). The A-V node can be divided into a superficial layer and a deep layer, and the deep layer further divided into a upper part and a lower part. The fibers in the superficial layer are vertical, and join with the lower part of the deep layer at the anterior extremity of the node. The lower part of the deep layer is the main axis of the node. The fibers in the lower part of the deep layer are longitudinal, and join with the RPE at the posterior extremity of the node. The fibers in the upper part of the deep layer are oblique and join with the LPE at the posterior extremity of the node, and mix with the lower part at the anterior extremity. The longitudinal dissociation of the anterior part of the His bundle is more distinct than that of the posterior part. The lower-left part of the bifurcating part of the bundle extend to form the posterior left branch, the upper-left and upper-middle parts of the bifurcating part extend to form the anterior left branch, and the right part and lower-middle part of the bifurcating part extend to form the right bundle branch. The morphological evidence of the dual or multiple conducting pathways, the longitudinal dissociation and the reentry pathways in the AVJ were discussed.