[Atresia of the pulmonary artery with intact interventricular septum. Apropos of 2 cases with prolonged course].

The authors report two cases of atresia of the pulmonary outflow with an intact interventricular septum; they are remarkable for their slow progression. In one patient the pulmonary perfusion was furnished by systemic arteries, while in the other it was by way of a patent ductus arteriosus. This second patient died following an attempted bi-cavo-pulmonary anastomosis. Such slow progression, which is the exception, is only possible if there is a substantial vicarious pulmonary circulation.