Kurosawa H, Becker A E
J Thorac Cardiovasc Surg. 1984 Apr;87(4):605-15.
There is a widely recognized relationship between the atrioventricular conduction bundle and the margins of the ventricular septal defects according to whether the defect is perimembranous or muscular. We have shown that this relationship may in turn be markedly influenced by the precise topography of the trabecula septomarginalis. Fifteen hearts, each with a ventricular septal defect, were studied by serial sectioning. Four hearts had an isolated ventricular septal defect in the setting of normal chamber connections and relations. One heart had a truncus arteriosus, seven hearts had Fallot's tetralogy, and three hearts exhibited complete transposition. In those hearts with outlet defects in which a bar of muscle separated the rim of the defect from the position of the conduction bundle, deficiency of the posterior limb of the trabecula septomarginalis permitted the right-sided margin of the conduction axis to "surface" in directly subendocardial position. Moreover, in some of these outlet defects, the conduction axis in the region of the branching bundle was exposed directly upon the crest of the muscular septum. The position of the medial papillary muscle complex was the best landmark to this potential danger area. In some of the examples of Fallot's tetralogy, we observed a firm muscle bar overlying the posteroinferior margin of the defect, which nonetheless was perimembranous. This protected the nonbranching component of the conduction axis in the anticipated danger area. Paradoxically, a deficiency in the trabecula septomarginatis then permitted the branching bundle to sit directly astride the septum along the inferior rim of the defect. We noted particularly marked variability of the atrioventricular conduction axis among the hearts with tetralogy. Our results suggest that close inspection during the operation may reveal whether or not a well-developed trabecula septomarginalis is present and permit conclusions to be drawn concerning the precise position of the atrioventricular conduction axis.
根据室间隔缺损是膜周部还是肌部，房室传导束与室间隔缺损边缘之间存在一种广为人知的关系。我们已经表明，这种关系反过来可能会受到隔缘肉柱精确形态的显著影响。通过连续切片研究了15颗患有室间隔缺损的心脏。4颗心脏在正常房室连接和关系的情况下有孤立的室间隔缺损。1颗心脏有法洛四联症，7颗心脏有法洛四联症，3颗心脏表现为完全性大动脉转位。在那些有流出道缺损的心脏中，一条肌肉条将缺损边缘与传导束的位置隔开，隔缘肉柱后肢的缺失使得传导轴的右侧边缘“暴露”于直接的心内膜下位置。此外，在一些这些流出道缺损中，分支束区域的传导轴直接暴露于肌性室间隔的嵴上。内侧乳头肌复合体的位置是这个潜在危险区域的最佳标志。在一些法洛四联症的例子中，我们观察到一条坚实的肌肉条覆盖在缺损的后下缘上方，尽管如此，它仍是膜周部的。这在预期的危险区域保护了传导轴的非分支部分。矛盾的是，隔缘肉柱的缺失然后使得分支束沿着缺损的下缘直接横跨室间隔。我们特别注意到法洛四联症患者心脏之间房室传导轴的显著变异性。我们的结果表明，手术期间的仔细检查可能会揭示是否存在发育良好的隔缘肉柱，并允许就房室传导轴的精确位置得出结论。
