[A new anatomo-clinical entity? The left superior vena cava obstructing the interior of the left atrium in association with a left-right shunt. Apropos of 2 cases].

The association of a left-right shunt with obstruction to the pulmonary venous return must not be ignored. Failure to recognise this may be fatal post-operatively. We have described here what we believe to be a new cause of supra-mitral obstruction: an abnormal left superior vena cava. The echocardiogram was essential in the diagnosis, and allowed us to establish, after surgical correction, that all abnormalities of the left auricle had disappeared.