[Left superior vena cava and anomalies associated with it].

In order to assess the frequency of persistent left superior vena cava as well as the associated congenital heart disease, 66 hearts were studied from 1277 necropsies of the pathologic collection of the Instituto Nacional de Cardiología "Ignacio Chávez". They were analyzed with the sequential segmental approach. It was determined: atrial situs types and modes of atrioventricular and ventricular arterial connections, morphology of the superior systemic venous return and associated cardiopathies. 33 hearts had situs solitus (group I) and 34 hearts had isomeric situs (Group II) (30 with dextroisomerism and 4 with levoisomerism). The group I showed double superior vena cava, the left one had continuation with the sinus coronary; in 25 of them the left brachiocephalic vein was absent, in 6 this vein was present, 5 with narrow lumen and in one it was dilated (specimen with atresia of the Tebesian valve). The more frequent congenital heart disease were ventricular septal defects, troncoconal cardiopathies and anomalies in the atrioventricular connection. The hearts of group II did not have coronary sinus; the venous connections were in the atrial roof. 19 hearts had double superior vena cava and 15 specimens had only the left one. The congenital heart disease in this group were complex with multiple patterns of association. Left superior vena cava is developed as a consequence of persistence of the continuation of the left anterior and left common cardinal veins with the left horn of sinus venosus when the proximal segment of these veins did not disappear. The left superior vena cava has surgical significance when congenital heart disease is present.