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THE LEFT-SIDED SUPERIOR VENA CAVA

1954; BMJ; Volume: 16; Issue: 4 Linguagem: Inglês

10.1136/hrt.16.4.423

1468-201X

Mark Campbell, D C Deuchar,

Abnormalities of the main systemic and pulmonary veins are arousing increasing interest.The object of this paper is to review our experience of 46 cases of the left-sided superior vena cava, including 4 examples of the much rarer condition where the inferior vena cava is absent.We wish also to discuss the type of cases in which these occur and their clinical significance.Abnormal drainage of the pulmonary veins has been discussed in several recent papersdrainage into the left superior vena cava by Snellen and Albers (1952), Gardner and Oram (1953), and Whitaker (1954), and drainage into the right atrium and the right side generally by Brody (1942), Smith (1951), Edwards (1953), and Swan et al. (1953).These groups will not, therefore, be included here, especially as we have seen few examples of the former. EMBRYOLOGYThe relevant embryology will be reviewed shortly to help in understanding these abnormalities.The Left-sided Superior Vena Cava.At one stage in the formation of the human embryo the sinu-atrial chamber becomes differentiated into the sinus venosus and the atrial chamber; and the septum dividing the latter into the right and left parts is formed in such a way that the sinus venosus communicates with the right part only.The sinus venosus lies transversely, dorsal to the atrial part of the heart, and its lateral parts are known as the horns, into each of which a duct of Cuvier opens.This is formed by the union of an anterior and a posterior cardinal vein, the former of these draining blood from the cephalic end and the latter from the caudal end of the embryo (Fig. 1).As development proceeds the heart as a whole moves caudally into the thorax HEAD END OF EMBRYO Rt. horn ofPost cardinal V. FIG.1.-Diagram showing an early symmetrical stage of the sinus venosus, the ducts of Cuvier, and the anterior and posterior cardinal veins on both sides.so that the ducts of Cuvier come to lie almost in the long axis of the embryo, draining from the cephalic end towards the heart.About the same time as the development of the liver and the common hepatic vein which drains into the right sinus horn, this half of the sinus venosus becomes larger than the left, and a transverse communication develops between the anterior cardinal veins so that the arrangement becomes as depicted in Fig. 2.