Subaortic stenosis is a blockage or narrowing at the outlet of the left ventricle, just below the aortic valve. That makes it hard for the left ventricle to pump blood to the body.

• Discrete subaortic stenosis is the most common form. In this type, a membrane made of fibrous tissue forms a blockage beneath the aortic valve.
• Tunnel subaortic stenosis is less common and more complex. In this type, the path between the ventricle and valve is narrow for the entire distance.

Subaortic stenosis can cause two main problems for the heart:

• The blockage can cause the left ventricle to work harder.
• The narrowing can cause fast and uneven blood flow that may damage the aortic valve, causing an otherwise normal valve to leak.

The specialists at Norton Children’s Heart Institute, affiliated with the UofL School of Medicine — the leading providers of pediatric heart care in Louisville and Southern Indiana — can help your child with subaortic stenosis.

The board-certified and fellowship-trained specialists at Norton Children’s Heart Institute have the skills and experience to provide a pinpoint diagnosis and develop a customized treatment plan for you and your child.

Norton Children’s has a network of outreach diagnostic and treatment services throughout Kentucky and Southern Indiana.

Subaortic Stenosis Symptoms

Doctors sometimes hear a heart murmur — a specific “whooshing” sound — because of the uneven blood flow through the narrowed area. More tests might reveal subaortic stenosis.

When the narrowing is severe, the child may have these symptoms:

• Chest pain
• Difficulty breathing
• Fainting
• Lack of appetite
• Low energy

We don’t know what causes subaortic stenosis in children. A family history of congenital heart defects might be a factor, but little is known about a specific cause.

Diagnosing Subaortic Stenosis in Children

A pediatric cardiologist will perform tests to diagnose subaortic stenosis:

• Cardiac MRI (magnetic resonance imaging): This test uses radio waves, magnets and a computer to form three-dimensional pictures of the heart. These pictures can show structural issues.
• Chest X-ray: This test shows pictures of the heart and lungs, and can show heart and lung issues, extra blood flow or fluid in the lungs caused by defects.
• Echocardiogram (echo): This test uses sound waves (ultrasound) to produce images of the heart and blood vessels’ structures on a screen. It can show structure of the heart and ductus arteriosus and also the function of the heart. Norton Children’s Heart Institute has 28 tele-echo locations throughout Kentucky and Southern Indiana.
• Electrocardiogram (ECG or EKG): This test checks the heart’s electrical activity to show damage or irregular rhythms, suggesting issues with the heart.
• Heart catheterization: This invasive procedure studies the structure, function, and provides direct pressure measurements of the heart. It also can be used to treat some heart defects.

Subaortic Stenosis Treatment, Complications and After Care

Subaortic stenosis in children is treated with open heart surgery that involves removing the subaortic membrane.

It’s possible that some of the membrane may be left behind, although it is unusual for that to cause any blockage. Most patients who undergo a subaortic resection go home three or four days after surgery.

Why Choose Norton Children’s Heart Institute

• Norton Children’s Hospital has been a pioneer in pediatric cardiothoracic surgery, performing Kentucky’s first pediatric heart transplant in 1986 and becoming the second site in the United States to perform an infant heart transplant.
• The American Board of Thoracic Surgery has certified our cardiothoracic surgeons in congenital heart surgery.
• The Adult Congenital Heart Association has accredited Norton Children’s Heart Adult Congenital Heart Disease Program as the only comprehensive care center in Kentucky and Indiana treating adults born with a heart defect.
• More than 17,000 children a year visit Norton Children’s Heart Institute for advanced heart care.
• Norton Children’s Heart Institute has offices across Kentucky and Southern Indiana to bring quality pediatric heart care closer to home.
• The Jennifer Lawrence Cardiac Intensive Care Unit (CICU) at Norton Children’s Hospital is the largest dedicated CICU in Kentucky, equipped with 17 private rooms and the newest technology available for heart care.