Obstructive ventricular septal defect in double outlet right ventricle

Three cases of double outlet right ventricle with evidence of interventricular obstruction are presented. In 2, the diagnosis was established by hemodynamic and cineangiocardiographic studies. The arterial oxygen saturation was normal, indicating a preferential flow of blood from the left ventricle into the aorta. The systolic pressure in the right ventricle and aorta was equal, and a significant gradient between the left ventricle and aorta was found. Gineangiocardiography showed a high aorta originating from the right ventricle and demonstrated that a small ventricular septal defect was the only outlet of the left ventricle.In the third case, postmortem examination revealed that the ventricular septal defect was very small. A combined subaortic and subpulmonary conus was present with a prominent subaortic component. The portion of the subpulmonary conus related to the ventricular septal defect was markedly distorted. This arrangement appeared to be responsible for the small size of the ventricular septal defect.It is suggested that the presence of an obstructive ventricular septal defect in double outlet right ventricle constitutes a developmental complex with characteristic clinical, hemodynamic and angiocardiographic features.