A complete atrio-ventricular defect consists of an atrial septal defect, a ventricular septal defect and a common atrio-ventricular valve. This results in a L → R shunt, both atrially and ventricularly. The common valve can be stenotic, regurgitant or both. Symptoms depend on the details of the lesions. In some cases additional defects are associated with this, such as tetralogy of Fallot’s or double outlet right ventricle. This creates a mixing lesion, which adds to the complexity of the anaesthetic management.