Wenink A C, Gittenberger-de Groot A C
Am J Cardiol. 1982 Jun;49(8):1959-71. doi: 10.1016/0002-9149(82)90216-8.
The anatomy of 25 hearts with a straddling mitral or tricuspid valve, or both, is described. Malalignment of atrial and ventricular septa is an essential feature of a straddling tricuspid valve, creating an inlet septal defect. Across this defect, the tricuspid valve straddles into the opposite (left ventricular) chamber, where it is separated from the mitral valve by a posterior muscular ridge, the posteromedial muscle. A straddling mitral valve requires an infundibular septal defect, predominantly of the malalignment type, in which the anterior part of the ventricular septum deviates to the left of the infundibular septum. The mitral valve straddles into the opposite (right ventricular) chamber, anterior to the trabecula septomarginalis. From normal developmental stages, it is concluded that valve formation takes place only after completion of ventricular septation. Any malformation of the valves is therefore considered to be superimposed on a primary malformation of the septum. The ventricular septum itself develops from three different components. Malseptation in the inlet portion of the embryonic heart lead to the characteristic septal malformation seen in straddling tricuspid valve. Malseptation in the outlet portion may lead to the septal malformation that characterizes straddling mitral valve.
本文描述了25例合并跨骑式二尖瓣或三尖瓣或二者皆有的心脏解剖结构。房间隔与室间隔的对位不良是跨骑式三尖瓣的一个基本特征，会导致流入道间隔缺损。通过这个缺损，三尖瓣跨骑进入对侧（左心室）腔室，在那里它被一个后肌嵴（后内侧肌）与二尖瓣分隔开。跨骑式二尖瓣需要一个漏斗部间隔缺损，主要是对位不良型，其中室间隔前部向漏斗部间隔左侧偏移。二尖瓣跨骑进入对侧（右心室）腔室，位于隔缘肉柱前方。从正常发育阶段可以得出结论，瓣膜形成仅在室间隔形成完成后发生。因此，任何瓣膜畸形都被认为是叠加在间隔的原发性畸形之上。室间隔本身由三个不同的成分发育而来。胚胎心脏流入道部分的间隔异常会导致跨骑式三尖瓣中所见的特征性间隔畸形。流出道部分的间隔异常可能导致跨骑式二尖瓣所特有的间隔畸形。
