Aortic valve stenosis symptoms & causes in children

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The term “stenosis” describes an abnormal narrowing within a structure of the body. Aortic valve stenosis, therefore, refers to the narrowing of the heart’s aortic valve. 

To picture what happens if your child has aortic valve stenosis, it’s helpful to have a solid understanding of the basic anatomy of the heart. The below diagram shows the heart's structures (click to enlarge).

  • Aortic valve stenosis is a narrowing that prevents the aortic valve from opening all the way. This can stop blood from flowing properly out of the heart, into the aorta and throughout the rest of the body.
  • In many cases, aortic valve stenosis is caused by a heart defect that is present at birth.
  • More rarely, children can develop aortic valve stenosis as a complication of rheumatic fever. Although a physical exam and an electrocardiogram may suggest a possible diagnosis of aortic valve stenosis, an echocardiogram is the definitive test to confirm the condition. Echocardiograms are painless, do not require an IV and only take about an hour.
  • Some children with aortic valve stenosis don’t need immediate treatment at all. Children with no outward symptoms can do very well for a long time with only regular monitoring by their treatment team.
  • Children with more advanced aortic valve stenosis are likely to require interventional catheterization or valve repair or replacement surgery. 

Interior View of the Heart Diagram

The parts of the heart affected by aortic valve stenosis are:

  • the left ventricle, one of two ventricles (chambers) that push blood to all of the body’s organs except the lungs (which are supplied by the right ventricle)
  • the aorta, the largest artery in the human body, which runs from the heart’s left ventricle all the way into the abdomen and is responsible for pumping blood out of the heart and into the rest of the body.
  • the aortic valve, which is located between the left ventricle and the aorta and directs blood from the left ventricle into the aorta (but not back the other way)

 When a child has aortic valve stenosis:

  • the heart has to work harder to pump blood into the body
  • the extra work can weaken the heart over time
  • the heart may only be able to push a reduced amount of blood through the body

What causes aortic valve stenosis in children?

Aortic valve stenosis in children is normally caused by either:

  • a birth defect, which can be any of the following:
    • a narrowed aortic valve
    • a condition called a bicuspid aortic valve, meaning that the child is born with an aortic valve that has only two leaflets instead of the usual three
    • valve leaflets that are fused together
    • valve leaflets that are unusually thick and do not open all the way

      Learn more about how Boston Children's treats congenital heart defects


  • rheumatic fever, a complicated disease that can develop in children already suffering from an infection of streptococcus bacteria, like strep throat or scarlet fever.

    Rheumatic fever is very rare in the United States today. It can lead to scarring of the tissue in the aortic valve, causing the valve to become constricted and narrowed. This scarring can also increase the likelihood of calcium deposits building up along the valve—a major risk factor for aortic valve stenosis in adulthood. 

Types of aortic valve stenosis 

What are the types of aortic valve stenosis?

The condition is classified according to its severity: mild, moderate, severe or critical.

Mild aortic valve stenosis
A child with mild aortic valve stenosis has very limited narrowing within the valve. These children will not show any outward symptoms; the only detectable problem is a pronounced, easily identified heart murmur. Children with this mild type of aortic valve stenosis are otherwise healthy and able to go about their daily lives without disruption.

Moderate aortic valve stenosis
Children with moderate aortic valve stenosis have a slightly more significant narrowing of the aortic valve, but usually show no outward symptoms and are otherwise healthy. A child with this type will have an easily detected and identified heart murmur. 

Severe aortic valve stenosis
A child with severe aortic valve stenosis has such an advanced degree of narrowing in the valve that the left ventricle may become very stiff.

Children with this type may also experience atrial fibrillation, an abnormal contraction of the heart’s ventricles caused by erratic electrical signals coming from the heart’s atria. Interventional catheterization or valve repair or replacement surgery are necessary to treat severe aortic valve stenosis.

Critical aortic valve stenosis
This, the most serious type of aortic valve stenosis, is usually present at birth. The newborn’s aortic valve is so narrowed that the heart cannot pump enough blood to nourish the body, so immediate intervention is needed—usually by surgically replacing the aortic valve.

Signs and symptoms of aortic valve stenosis

What are the symptoms of aortic valve stenosis?

Many children with aortic valve stenosis show no outward symptoms since they are in the mild to moderate stages of the condition. Usually, the only identifiable symptom in these cases is a pronounced heart murmur

As aortic valve stenosis progresses, children may experience:

  • fainting
  • shortness of breath or difficulty breathing
  • irregular heartbeats or heart palpitations
  • chest pain
  • dizziness during or immediately after physical activity
  • fatigue

You should seek treatment from a qualified medical professional right away if you notice any of these warning signs in your child. 

Frequently Asked Question (FAQ) about aortic valve stenosis

Q: Will my child be OK? How much will aortic valve stenosis disrupt her life?
Your child’s long-term health and course of treatment depend greatly on her unique circumstances, especially:

  • her age at the time of diagnosis
  • how narrowed the aortic valve has become at the time of diagnosis
  • her symptoms
  • her tolerance for specific medications or procedures
  • your family’s preferences for treatment

Children with mild or moderate aortic valve stenosis may not need any immediate intervention, and can do well for long periods of time with regular monitoring and checkups by their treatment team.

If your child has a serious case of aortic valve stenosis, she will need interventional catheterization or valve surgery. However, the good news is that the majority of children who undergo these procedures for aortic valve stenosis make a full recovery and go on to live healthy, normal adult lives.

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Q: Is aortic valve stenosis a common heart problem? Are some children more likely to develop it than others?
A: Aortic valve stenosis makes up about 3 to 6 percent of all cases of congenital heart conditions. Four times as many boys as girls are born with aortic valve stenosis.

Aortic valve stenosis caused by complications of rheumatic fever is less common, especially since rheumatic fever itself is becoming increasingly rare in the United States. 

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Q: Does my child need to take antibiotics before routine medical or dental procedures?
A child with aortic valve stenosis may need to periodically take antibiotics in order to prevent an infection called bacterial endocarditis, even if his aortic valve has been surgically replaced. Bacterial endocarditis can cause serious damage to the inner lining of the heart and its valves.

Children with heart conditions may be vulnerable to developing endocarditis while undergoing medical procedures that could release bacteria into the bloodstream. In these cases, a regimen of antibiotics might be prescribed before the child has the procedure. You should always let medical personnel know about your child’s aortic valve stenosis before making arrangements for a medical procedure, even if the procedure seems minor or unrelated to your child’s cardiac care.

If your child has aortic valve stenosis, but no other cardiac problems, he probably will not need antibiotics before a routine dental procedure (for example, a teeth-cleaning).

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Q: Does my child have to cut back on physical activities?
A: Whether your child needs to cut back significantly on activities depends greatly on her age, how narrowed the aortic valve has become at the time of diagnosis and what symptoms (if any) she is experiencing. 

If your child has mild aortic valve stenosis with no outward symptoms, she may not need to change her daily activities and can continue to take part in sports and recreational play. If your child has more a pronounced narrowing of the aortic valve, she may need to limit activities that call for a higher level of exertion. If your child has a serious case (or is preparing to undergo interventional catheterization, surgical valve repair or valve replacement), she may need to stop certain high-impact, high-stress activities.

Your child’s treating clinician will evaluate her individual situation and advise you of any necessary restrictions or changes in physical activity.

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Q: Is my child at risk of having a heart attack? 

A: One of the most common misconceptions about aortic valve stenosis is that a child diagnosed with the condition is at high risk of a sudden heart attack. 

Most children with aortic valve stenosis are diagnosed when they are still comfortable and free of outward symptoms. Thanks to available diagnostic procedures and imaging technology, the condition can be detected even when the only noticeable symptom is a heart murmur. This gives clinicians the opportunity to start monitoring kids with aortic valve stenosis right away, and to easily “stay on top of” the progression of the condition with regular echocardiograms and exams.

Newborns with critical aortic valve stenosis tend to have much more serious symptoms and much more severe narrowing of the valve at the time of diagnosis. However, sophisticated imaging and intervention procedures—including interventional catheterization and valve replacement—enable clinicians to take immediate action.

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Q: What do I need to look out for once my child has been diagnosed with aortic valve stenosis?
Parents of children with aortic valve stenosis should always be watchful for changes in behavior, appearance, activity level and respiration.

You should seek medical help immediately if your child experiences:

  • fainting
  • heart palpitations or an irregular heartbeat
  • shortness of breath or difficulty breathing
  • chest pain
  • clammy skin or the feeling of a “cold sweat”
  • dizziness
  • pale, ashen color in the face
  • racing heartbeat
  • rapid breathing
  • swollen feet or legs

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Q: Can Boston Children’s treat a baby in the womb who has been diagnosed with aortic valve stenosis?
A: Yes. Boston Children’s Fetal Cardiology Program can:

  • diagnose, or confirm an earlier diagnosis, of heart defects using fetal ultrasound, echocardiography or magnetic resonance imaging (MRI)
  • work with families to devise customized treatment plans
  • perform fetal interventions such as aortic valve dilation, atrial septum dilation and pulmonary valve dilation

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Q: Does Boston Children’s offer genetic testing for aortic valve stenosis?
Yes. Boston Children’s  Cardiovascular Genetics Programprovides several clinical services to test for heart conditions, including aortic valve stenosis, and also offers genetic counseling. 

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Q: Is there a cure for aortic valve stenosis?
A: In general, aortic valve stenosis is a progressive condition, meaning that the valve will continue to narrow over time and further intervention will eventually become necessary.

The good news is that, even when aortic valve stenosis is advanced, interventional catheterization and valve surgery both have an excellent success rate for restoring normal heart function and blood flow.  

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