Above. Both the pulmonary artery (PA) and aorta (AO) arise from the right ventricle in double-outlet right ventricle (DORV). Blood from the left ventricle must exit through a large ventricular septal defect (VSD). Most often the great arteries, PA and AO, are side by side and separated by the conus septum. In DORV, the pulmonary and aortic valves are at the same level. Subtypes of DORV are based upon the position of the VSD and presence or absence of pulmonary stenosis or right ventricular outflow tract obstruction (RVOTO).