Congenital arteriovenous malformations are rare causes of congestive cardiac failure in neonates. The most common sites are in the head and liver, but other sites include the thorax, the abdomen and the limbs. The onset of failure is usually not in the immediate neonatal period, but later on in life, albeit that lesions such as the arteriovenous malformation of the vein of Galen, and other arteriovenous malformations in different locations which produce high flow can present early. We describe here the first case, to the best of our knowledge, of prenatal detection of an intrathoracic arteriovenous malformation producing neonatal cardiac failure, which was successfully treated by surgery postnatally.