complete atrioventricular septal defect unbalanced complete common atrioventricular canal csmith unbalanced complete atrioventricular septal defect MPheno.ontology MP:0011673 2012-04-20T01:32:23Z an unbalanced complete atrioventricular septal defect occurs when the atrioventricular junction is predominantly committed to either the right or left ventricle, leading to hypoplasia of the opposing ventricle receiving the smaller amount of blood Fyler:1132