Subvalvular aortic stenosis (AS) is a rare congenital heart defect in which the left ventricle is narrowed below the level of the aortic valve resulting in obstruction to blood flow out of the heart. The condition is also known as subaortic stenosis.

Normally, blood passes through the aortic valve en route to the aorta. In subvalvular aortic stenosis, a narrowed area below the aortic valve limits blood flow, increasing the workload for the left ventricle. This can cause the left ventricle to enlarge and fail. If your condition causes moderate to severe symptoms or related valve disease, you may need heart valve surgery to treat the condition.

Causes of subvalvular aortic stenosis

Subvalvular aortic stenosis is a congenital heart defect that occurs during fetal development. The precise cause is unknown, but genetics may play a role. Subaortic stenosis has also been associated with several congenital syndromes.

Symptoms of subvalvular aortic stenosis

Children who have subvalvular aortic stenosis may not have symptoms, but the condition can worsen with age. In more severe cases in babies, symptoms include:

  • Rapid breathing
  • Rapid heart rate
  • Inability to eat
  • Heart failure

In more severe cases in older children, symptoms include:

  • Fatigue
  • Fainting
  • Chest pain

Why choose Ohio State for subvalvular aortic stenosis treatment?

Ohio State’s Wexner Medical Center offers a team approach to congenital heart disease, which means each patient is evaluated by an Adult Congenital Heart Disease (ACHD) specialist, and when appropriate, a cardiac surgeon, an imaging specialist and an interventional cardiologist with training in congenital heart disease. This integrated approach means that each patient’s disease is treated individually, with that particular patient’s needs, and physical condition, in mind.

Anyone who has ever been diagnosed with and/or treated for subvalvular aortic stenosis should have lifelong care from a cardiologist who specializes in congenital heart defects. Ohio State's Wexner Medical Center provides this care from birth to adulthood. We partner with Nationwide Children’s Hospital to provide the resources necessary for the care of adult congenital cardiac patients through the Columbus Ohio Adult Congenital Heart (COACH) Disease Program.

The COACH program focuses on:

  • Adults with congenital heart disease
  • Pulmonary hypertension
  • Cardiovascular connective tissue disorders
  • Pregnancy in women with heart disease
  • Transition of adolescents with congenital heart disease into adult congenital heart disease care
  • Training of future adult congenital heart disease providers

How Ohio State diagnoses subvalvular aortic stenosis

Tests used to diagnose subvalvular aortic stenosis include:

Electrocardiogram (EKG/ECG) – A test that records the electrical activity of the heart.

Echocardiogram (also called echo) – A test that uses sound waves to assess the function and structure of the heart muscle and valves.

Chest X-ray – A radiograph or picture of the heart and lungs including blood vessels, ribs and bones of the spine.

Cardiac MRI (cardiac magnetic resonance imaging or CMR) – A noninvasive, sophisticated imaging procedure that uses large magnets and a computer to produce detailed images of the structure and function of the heart while it is beating.

Cardiac catheterization – A procedure to measure pressures in the heart and check for problems in the coronary arteries. A long, thin tube (catheter) is inserted into an artery or vein in the groin, arm or neck, and then threaded to the heart. The physician injects a contrast solution into the artery and takes X-rays to check for blockage and other abnormalities.

How Ohio State treats subvalvular aortic stenosis


Currently, there are no medications used to treat subvalvular aortic stenosis. In cases where patients develop heart failure, medications such as beta-blockers or angiotensin receptor blockers (ACE-inhibitors) may be used, but these should be used cautiously under the direct supervision of a cardiologist.


For patients with moderate or severe obstruction that has a significant impact on the heart function, surgery is required to relieve the obstruction. This most often involves removal of the excess muscle or tissue. In severe cases that also affect the function of the aortic valve, valve repair or replacement may be necessary.

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