Alveolar capillary dysplasia with misalignment of the pulmonary veins is an uncommon disorder that affects the lung vasculature development in the neonatal period and leads to pulmonary hypertension. We describe two patients with alveolar capillary dysplasia associated with left-sided obstructive heart defects with two different genetic variants. Our cases highlight the importance of early recognition of this disease in the setting of persistent and supra-systemic pulmonary hypertension despite surgical correction of the associated lesions. Identification of these cases will facilitate the development of a multidisciplinary approach and provide guidance to the affected families.

We describe an infant with hypoplasia of the left heart diagnosed prenatally who, at birth, had signs of severe pulmonary venous obstruction. Echocardiography indicated normally connecting pulmonary veins, and showed a paradoxical right-to-left shunt across a patent oval foramen. Postmortem examination revealed that the obstruction was due to a divided left atrium, or cor triatriatum sinister, with an imperforate muscular diaphragm separating completely the two components of the divided atrium.