Tabriz University of Medical Sciences Journal of Cardiovascular and Thoracic Research 2008-5117 13 4 2021 12 12 Non diagnosed PAPVC induce large reverse venovenous shunt after modified Fontan surgery: A case report of a rare anomaly and embolization therapy 364 366 10.34172/jcvtr.2021.22 EN Zahra Alizadeh Sani Abdolrahim Ghasemi Shabnam Mohammadzadeh Zahra Khajali Mohaddeseh Behjati Roohallah Alizadehsani Abbas Khosravi Saeid Nahavandi Sheikh Mohammed Shariful Islam Journal Article 10.34172/jcvtr.2021.22 2020 09 20 2021 02 12 Fontan operation is a reliable palliative surgery for patients with single ventricle physiology. Still, the development of complication is common; one of these complications that need to interventional approach is veno-venous collaterals between systemic and pulmonary veins. A 16-yearoldgirl with a history of modified Fontan operation at 9 years ago was referred with progressive cyanosis and dyspnea on exertion. In contrast trans-thoracic echocardiography (TTE), no fenestration was seen in Fontan circulation. Cardiac magnetic resonance revealed partial anomalous pulmonary vein connection (PAPVC) from left upper pulmonary vein to vertical vein and then into the in nominate vein and SVC with the reverse flow from superior vena cava (SVC) to left upper pulmonary vein(LUPV). This anomalous vein became severe engorged and tortuous. Possibly, LUPV and the verticalvein was dilated gradually as a result of increased pressure in the Fontan circuit. Finally, she underwent successful coil embolization in the midpart of the vertical vein. The oxygen saturation increased from80% to 93%.