Double outlet right ventricle with subvalvular aortic stenosis.

A case of double outlet right ventricle had progressive muscular subvalvular aortic stenosis unrelated to the ventricular septal defect. Ventricular systolic pressures were identical and higher than aortic, and the gradient was within the right ventricle. Selective angiocardiography showed a hypertrophied subaortic conus obstructing the right ventricular outlet. Serial haemodynamic and angiographic studies revealed progression of the subaortic stenosis which may have been related to an earlier pulmonary artery banding operation. Distal conal hypertrophy is postulated as the cause of the obstruction.