Atrioventricular Canal Defect

Abstract

The majority of patients with complete AVC defect are children with trisomy 21 syndrome. AVC defect may be partial, manifesting as ASD and mitral valve cleft or ­complete, manifesting with ASD, VSD and a common AV valve. Many patients with AVC defect manifest with lesions in between partial and complete AVC defect. Combination of right ventricular hypertrophy and left axis deviation (rather than right axis deviation as one would expect secondary to right ventricular hypertrophy) on an electrocardiogram should alert to the possibility of AVC defect. Surgical repair in children with complete AVC defect depends on the balance of the common AV over the two ventricles. Straddling or hypoplasia of one side of the common AV valve will lead to hypoplasia of the corresponding ventricle which would prohibit biventricular repair. Children with hypoplasia of one of the ventricles will require univentricular repair (Glenn shunt followed by Fontan procedure).