Complete AV septal defect A complete atrioventricular septal defect, also called a complete common AV canal defect (see figure), consists of a Large ostium primum atrial septal defect (ASD) in the anteroinferior aspect of the septum Contiguous nonrestrictive inlet ventricular septal defect Common AV valve orifice A complete AV septal defect is a single large central defect in the septation of the heart.