MRI of marked atrial dilatation with impingement on pulmonary venous return in a patient with an atriopulmonary Fontan anastomosis for tricuspid atresia. MRI of marked atrial dilatation with impingement on pulmonary venous return in a patient with an atriopulmonary Fontan anastomosis for tricuspid atresia. Right atrium measures 7×7.5 cm. Image courtesy of Cynthia K Rigsby, Children's Memorial Hospital, Chicago, Illinois, USA. Barbara J Deal, and Marshall L Jacobs Heart 2012;98:1098-1104 Copyright © BMJ Publishing Group Ltd & British Cardiovascular Society. All rights reserved.