Subvalvular Aortic Stenosis.

Obstruction of the left ventricular outflow tract (LVOT) occurs in six out of 10,000 live births. The obstruction occurs in the aortic valve level in 71 percent, in subvalvular level in 14 percent, and supravalvular level in 8 percent of cases. Subvalvular aortic stenosis (AS) can be either a fixed stenosis resulting from subaortic membrane or a dynamic stenosis because of hypertrophic cardiomyopathy. Here, we report a patient with subaortic membrane who became symptomatic in her sixth decade of life. Echocardiography is the preferred diagnostic modality. Indications for surgery include symptoms, LVOT gradient of 50 mmHg or more, and development of significant aortic regurgitation.