Endocardial cushion defect

Endocardial cushion defect, also known as atrioventricular canal malformation, atrioventricular septal defect, or atrioventricular canal defect, is a congenital heart malformation resulting from abnormal embryonic development. During embryonic development, the endocardial cushions contribute to the formation of the mitral valve, tricuspid valve, atrial septum, and ventricular septum. Therefore, abnormal development of the endocardial cushions leads to a variety of cardiac malformations, including large ventricular septal defects inferior to the atrioventricular valves, atrial septal defects superior to the atrioventricular valve plane, and single or common atrioventricular valve orifices. More than half of patients with endocardial cushion defects also have Down syndrome.