Biatrial connection of partial anomalous pulmonary venous return

We describe an extremely rare case of partial anomalous pulmonary venous return in a 3-year-old boy with an abnormal connection between the right upper pulmonary vein and the right middle pulmonary vein, which created biatrial communication hemodynamically. Patch closure on the orifice of the right upper pulmonary vein was performed to avoid distortion or kinking of the right pulmonary veins and the connection.