Double outlet right ventricle: anatomic types and associated anomalies

The necropsy specimens of 33 examples of double outlet right ventricle were studied. In 31 of the 33 cases, a ventricular septal defect (VSD) was present, and in two the ventricular septum was intact. Two of the VSDs appeared small and obstructive, while the remainder were of the large variety. Among the 31 cases the VSD was located in one of four locations: below the aortic valve (15 cases), below the pulmonary valve (nine cases), below both valves (four cases), and remote from either semilunar valve (three cases). Associated cardiovascular anomalies were present in 28 of the 33 cases and were usually obstructive to blood flow. Pulmonary stenosis or subpulmonary stenosis, or both, were confined to patients with the subaortic location of VSD and were seen in six of 15 such cases. Obstruction to systemic flow, either subaortic or within the aortic arch, was observed in 19 cases. There was a strong tendency for obstruction to systemic flow to be associated with a subpulmonary VSD. Various anomalies, usually of the mitral apparatus, causing obstruction to pulmonary venous flow were common but without a trend for association with a particular location of the VSD.