Narrowing of the left ventricle of the heart just below the aortic valve through which blood must pass on its way up into the aorta. The narrowing cuts the flow of blood.

Subaortic stenosis may be congenital (present at birth) or acquired as part of a particular form of heart disease known as “idiopathic hypertrophic subaortic stenosis” (IHSS). Treatment options include drugs and surgery.