Combined discrete subaortic stenosis and ventricular septal defect in infants and children.

Eight patients, aged 1 to 8 years, with discrete subaortic stenosis (DSS) and ventricular septal defect (VSD) were studied by 2-dimensional (2-D) and M-mode echocardiography. Initial cardiac catheterization and angiocardiography showed VSD and other associated cardiac lesions, including coarctation of the aorta and patent ductus arteriosus. None had evidence of DSS. Six patients underwent surgical repair of the associated lesions, but none required closure of the VSD. Ultimately, 6 patients had spontaneous closure of VSD, and 2 had a residual small VSD. Subsequent serial echocardiography showed evidence of subaortic membrane, prompting repeat cardiac catheterization, which confirmed moderate to severe peak systolic pressure gradients between the left ventricle and ascending aorta. Surgical resection of the membrane was performed in 5 patients. Thus, in patients with small or spontaneously closed VSDs, DSS may develop. Evaluation of the left ventricular outflow tract area is recommended in patients with small or closed VSD in whom a significant heart murmur or electrocardiographic abnormality remains.