Anderson Robert H, Sarwark Anne E, Spicer Diane E, Backer Carl L
Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
Division of Cardiovascular-Thoracic Surgery, Lurie Children's Hospital, Chicago, IL, USA
Multimed Man Cardiothorac Surg. 2014 Dec 24;2014. doi: 10.1093/mmcts/mmu026. Print 2014.
Holes between the ventricles are the commonest congenital cardiac malformations. As yet, however, there is no consensus as to how they can best be described and categorized. In this, our third exercise in cardiac anatomy, we address the issue of classification of ventricular septal defects. We begin our demonstration by analysing the normal heart. We show that the larger part of the ventricular septum is made up of its muscular component. The membranous part accounts for only a small portion, which is located centrally within the cardiac base. This small membranous part forms a boundary between the right-sided chambers and the aortic root. Holes at this site, therefore, which account for the commonest defects closed surgically, will open centrally in the cardiac base, being located postero-inferiorly relative to the supraventricular crest. We then show that the larger part of the crest itself is a free-standing muscular sleeve, which lifts the leaflets of the pulmonary valve away from the cardiac base. Only a very small part of the muscle forming the right ventricular outlet is located in the septal position. Turning our attention to malformed hearts, we show how holes between the ventricles can open centrally at the cardiac base, open to the inlet or outlet of the right ventricle or open within the substance of the apical muscular septum. We demonstrate, however, that description of such geographical location of the defects does not paint the full picture, since lesions with markedly different phenotypic features can open in comparable geographic locations. We illustrate how it is the phenotypic features, as seen from the right ventricle, which convey the crucial information for the surgeon with regard to the location of the atrioventricular conduction axis, using hearts with holes opening to the inlet of the right ventricle with muscular as opposed to partially fibrous borders to emphasize this point. We continue by showing how holes with different phenotypes can also open to the outlet of the right ventricle, the key feature in this regard being malalignment between the apical muscular septum relative to the muscular outlet septum or its fibrous remnant. Malalignment can also be found between the apical ventricular septum and the atrial septum, this being shown in a defect opening to the inlet of the right ventricle. We conclude by emphasizing that, so as to bring together all the information of surgical significance, it is necessary to take note of the geographical location of holes between the ventricles, their phenotypic features and the presence or absence of malalignment between the septal components.
心室间孔洞是最常见的先天性心脏畸形。然而，对于如何最好地描述和分类这些畸形，目前尚无共识。在本次心脏解剖的第三次练习中，我们将探讨室间隔缺损的分类问题。我们从分析正常心脏开始演示。我们发现室间隔的大部分由其肌肉部分组成。膜部仅占一小部分，位于心脏基部的中央。这个小的膜部形成了右侧腔室与主动脉根部之间的边界。因此，位于该部位的孔洞是手术闭合的最常见缺损，它们将在心脏基部中央开口，相对于室上嵴位于后下方。然后我们展示嵴本身的大部分是一个独立的肌肉套，它将肺动脉瓣叶从心脏基部抬起。构成右心室出口的肌肉中只有非常小的一部分位于间隔位置。将注意力转向畸形心脏，我们展示了心室间的孔洞如何在心脏基部中央开口、开口于右心室的入口或出口，或者开口于心尖肌肉间隔内。然而，我们证明，对这些缺损地理位置的描述并不能完整地说明情况，因为具有明显不同表型特征的病变可以在类似的地理位置开口。我们举例说明，从右心室观察到的表型特征如何为外科医生提供关于房室传导轴位置的关键信息，通过有孔洞开口于右心室入口且边界为肌肉性而非部分纤维性的心脏来强调这一点。我们接着展示具有不同表型的孔洞也可以开口于右心室出口，在这方面的关键特征是心尖肌肉间隔相对于肌肉性出口间隔或其纤维残余物的排列不齐。心尖室间隔与房间隔之间也可发现排列不齐，这在一个开口于右心室入口的缺损中得到体现。我们最后强调，为了汇总所有具有手术意义的信息，有必要注意心室间孔洞的地理位置、它们的表型特征以及间隔成分之间是否存在排列不齐。
