Lo H M, Lin F Y, Cheng J J, Tseng Y Z
Department of Medicine, Taiwan Provincial Tao-Yuan General Hospital, Taipei, Republic of China.
Int J Cardiol. 1995 Oct;51(3):273-82; discussion 283-84. doi: 10.1016/0167-5273(95)02419-w.
Despite major success in the treatment of atrioventricular (AV) node reentrant tachycardia using either catheter ablation or surgery, the morphologic basis underlying AV node reentry is not yet clear. A canine model of AV node reentrant tachycardia was used to examine the histologic features of the reentry circuit. AV node reentrant tachycardia was created in 4 of 8 dogs by a right atrial division which divided the right atrial free wall and the atrial septum into upper and lower portions on a plane between the mid-right atrial free wall and the fossa ovalis. The AV junctional area of all dogs were serially sectioned on a plane that was perpendicular to the AV annulus and the septum. The slices were stained with Masson's trichrome technique. The connections between atrial fibers and the compact AV node and the common AV bundle were examined, and comparison of the histologic features between dogs with and without AV nodal re-entry was made. The histologic examinations showed that, in all dogs, the operation scar was remote from the AV junctional area leaving the Koch's triangle intact. The compact node received its atrial inputs mainly from the anterosuperior and posterior aspects of the Koch's triangle. However, both atrial inputs gave off superficial (subendocardial) fibers that by-passed the compact node to terminate at the base of tricuspid valve. These superficial fibers might function as the proximal link between the dual AV nodal inputs by means of lateral connections. There was no bypass connection between atrial fibers and the common AV bundle. The histologic features of the AV junctional area was not different between dogs with and without AV nodal reentry. In conclusion, AV nodal reentry involves the anterior and posterior atrio-nodal inputs which function as dual AV nodal pathways, and the superficial bypass fibers form the proximal linkage between the two inputs. These structures, together with the compact node, complete the reentry circuit.
尽管在使用导管消融或手术治疗房室（AV）结折返性心动过速方面取得了重大成功，但AV结折返的形态学基础尚不清楚。采用犬AV结折返性心动过速模型来研究折返环路的组织学特征。通过右心房分隔术在8只犬中的4只中诱发AV结折返性心动过速，该手术在右心房游离壁和房间隔之间的平面上，将右心房游离壁和房间隔分为上下两部分，该平面位于右心房游离壁中部和卵圆窝之间。所有犬的房室交界区均在垂直于房室环和间隔的平面上进行连续切片。切片用Masson三色染色技术染色。检查心房纤维与致密房室结和共同房室束之间的连接，并对有和没有房室结折返的犬的组织学特征进行比较。组织学检查显示，在所有犬中，手术瘢痕远离房室交界区，科赫三角保持完整。致密结的心房输入主要来自科赫三角的前上方和后方。然而，这两个心房输入均发出浅表（心内膜下）纤维，这些纤维绕过致密结，终止于三尖瓣基部。这些浅表纤维可能通过侧向连接作为双房室结输入之间的近端连接。心房纤维与共同房室束之间没有旁路连接。有和没有房室结折返的犬之间，房室交界区的组织学特征没有差异。总之，房室结折返涉及前、后房室结输入，它们作为双房室结径路起作用，浅表旁路纤维形成两个输入之间的近端连接。这些结构与致密结一起构成了折返环路。
