atrioventricular septal defect 2010-09-27T02:50:46Z AV septal defect AVC AVCD AVSD Atrioventricular canal (endocardial cushion defect) ECD Fyler:1100 MP:0010412 MPheno.ontology The term name is common usage among cardiologists and refers to the specific state in the definition (abnormal communications); do not confuse with parent term. atrioventricular canal defect csmith defects in the thin membranous structure between the right atrium and left ventricle that arise from faulty development of the embryonic endocardial cushions; the spectrum ranges from a primum atrial septal defect and cleft mitral valve, known as a partial atrioventricular septal defect (partial AVSD), to defects of both the primum atrial septum and inlet ventricular septum and the presence of a common atrioventricular valve, referred to as complete atrioventricular septal defect (complete AVSD) endocardial cushion defect abnormal atrioventricular septum morphology