A one-day-old term male was referred to our centre from the periphery because of cyanosis unresponsive to oxygen. He was initially well, and was then noted to be “dusky” subsequent to a bout of vomiting. He had been induced at 39 weeks because of concerns regarding his small size for gestational age.

Physical examination revealed normal pulses, increased right ventricular activity, a loud and single second heart sound and a soft, systolic ejection murmur. Electrocardiography showed generous right ventricular forces, but no right atrial enlargement. A chest radiograph was unremarkable. Echocardiography revealed pulmonary veins that seemed to come to a confluence behind the left atrium, and then join an enlarged superior caval vein. An interatrial communication of 4 millimetres diameter was also noted, with flow from right-to-left across it.

Magnetic resonance imaging was performed to detail the vascular anatomy. This revealed usual atrial arrangement, with bidirectional flow across a sinus venosus defect. A coronal view at the level of the pulmonary veins demonstrated the confluent pulmonary veins entering directly the posterior wall of the right atrium (Fig. 1). The right atrium was seen to be dilated, consistent with volume overload. A sagittal view showed the inferior and superior caval veins in long axis joining the right atrium. The confluence of all four pulmonary veins joined the posterior wall of the right atrium directly, just beneath the junction of the superior caval vein and the right atrium (Fig. 2).

Figure 1. Pulmonary venous connection to superior vena cava and right atrial junction.

Figure 2. Long axis view shows the confluence of pulmonary veins joining the right atrium beneath the superior vena cava and right atrial junction.