Caplike double-horned double-outlet right ventricle. Report of two cases.

Two patients with a rare form of double-chambered, double-outlet right ventricle (DORV) are described. Both patients had associated pulmonary stenosis, ventricular septal defect, and a large tricuspid valve whose chordal attachments crossed the right ventricular outflow tract. The angiocardiographic, echocardiographic, and operative findings were distinctive. The right ventricle was positioned as a "cap" sitting atop the ventricular septal defect at the cephalad end of the left ventricle. The right ventricle, with its two "horns," was likened to a rider straddling a saddle. Tricuspid chordal attachments extended into each of the two right ventricular "horn." No repair was performed in the asymptomatic patient. The other repair involved closure of the tricuspid orifice and insertion of a valved extracardiac conduit from the right atrium to the pulmonary artery.