We had two cases of neonates with hypoplastic left heart syndrome and intact atrial septum who had unique levoatriocardinal veins. Contrast-enhanced CT and angiography revealed that previously unknown communicating vessels ran from the top of the left atrium and drained into the right atrium. We emphasise that transcatheter atrial septostomy should be performed not through these communicating vessels but using the trans-septal approach in neonates with hypoplastic left heart syndrome and an intact atrial septum.

The levoatriocardinal vein is the embryological remnant of the connection between the pulmonary and systemic venous systems. It is a rare lesion that usually occurs in the presence of left-sided obstruction, developing as a pathway for decompression of the pulmonary veins. We report the first case of a levoatriocardinal vein in a patient with D-transposition of the great arteries.

We report two cases with levoatriocardinal vein and partial anomalous pulmonary venous drainage in left-sided obstructive lesions. This association may be difficult to recognise by echocardiography. Cardiac CT and MRI were crucial to define the diagnosis and to tailor the best therapeutic option.

The levoatriocardinal vein provides alternative egress from the left atrium to the systemic veins in left-sided obstructive lesions. Although rare, it has been described in association with hypoplastic left heart syndrome. We report a case of hypoplastic left heart syndrome with levoatriocardinal vein and aberrant right subclavian artery where cardiac magnetic resonance imaging/angiography proved to be a valuable imaging modality for pre-operative evaluation.