A full-term newborn was referred to our paediatric intensive care unit for persistent cyanosis. There was no dyspnoea and cardiac auscultation was normal. Chest radiography showed a heart of normal size with pulmonary vascular overload. No improvement in capillary saturation was observed after a hyperoxia test, suggesting cyanotic congenital heart disease. An umbilical venous catheter was then placed in order to administrate intravenous prostaglandin therapy, and capillary saturation increased from 56 to 83%. Afterwards, the patient was transferred to our hospital to perform echocardiography and to continue care. Two-dimensional (2D) echocardiography revealed a transposition of the great arteries ( Fig. 1 ). On 2D and 3D echocardiography, the umbilical catheter was seen passing through the foramen ovale ( Fig. 2 , Videos 1 and 2 ). Left-to-right atrial shunt was then sufficient to discharge the left atrium ( Fig. 2 A, Video 1 ). As soon as the catheter was removed, the foramen ovale became restrictive, with a concomitant decrease in saturation to 55% ( Fig. 3 A) . A Rashkind procedure was performed, which improved blood flow between the two atria ( Fig. 3 B) and increased capillary saturation to 85%. The fossa ovalis membrane, which had restricted the blood flow ( Fig. 3 C, Video 3 ), was torn up by the procedure ( Fig. 3 D, Video 4 ).
