We discuss the clinical course of aneonate with idiopathic hypertrophic cardiomyopathy who showed rapid progression of stenosis of the right ventricular outflow tract and reduction in size of the right ventricular cavity due to thicken ing of the ventricular septum. Medical treatment proved unsuccessful. We suggest that balloon atrial septostomy combined with construction of a Blalock-Taussig shunt may be effective in view of the hemodynamics, which mimic pulmonary atresia with intact interventricular septum.
