Noonan syndrome with double-chambered right ventricle.

The association of Noonan syndrome and a double-chambered right ventricle has not been reported previously in the medical literature. We report two patients with Noonan syndrome associated with pulmonary valve stenosis and double-chambered right ventricle due to anomalous hypertrophied muscle bundles. Pulmonary valve stenosis was operated on. However, hypertrophied muscle bundles were not resected, as they caused no obstruction to blood passage. Postoperative follow-up examinations revealed no symptoms. In conclusion, in those with Noonan syndrome there may be anomalous muscle bundles in the right ventricular cavity. It may not be necessary to resect them if they do not obstruct the right ventricular outflow tract.