Pediatric Hypoplastic Left Heart Syndrome

Pediatric Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS) is a congenital heart condition in which children are born with four defects affecting the left side of the heart.

What is Pediatric Hypoplastic Left Heart Syndrome?

Four defects affecting the left side of the heart, which are:

  • Left ventricle: Responsible for pumping blood out to the body is too small
  • Mitral valve: Normally controls blood flow between the two left chambers and is either not formed or very small
  • Aortic valve: Normally regulates blood flow from the heart to the aorta and is either not formed or very small
  • Aorta: Large artery leading from the heart to the body is underdeveloped or too small

The most critical defect in all cases is the left ventricle. It is normally a very strong muscle, but in children with HLHS, its function is so impaired it cannot pump enough oxygen-rich blood to meet their body’s needs. This creates a life-threatening condition that requires immediate as well as ongoing treatment.

If your child has been diagnosed with hypoplastic left heart syndrome (HLHS), you want the best experts possible providing the immediate treatment your child needs. Physicians at Children’s are world-class subspecialists from UT Southwestern whose level of experience with this rare condition is unparalleled in North Texas.

What are the signs and symptoms of Pediatric Hypoplastic Left Heart Syndrome?

Children born with HLHS appear normal at first but as they adjust to life outside the womb, which includes maintaining their own blood flow, they will quickly become sick.

Symptoms of HLHS can start showing in the first few hours or days of life and can include:

  • Skin that appears ashen or blue from poor circulation (cyanosis)
  • Pale skin
  • Sweaty or clammy skin
  • Cool skin
  • Heavy or rapid breathing
  • Rapid heart rate
  • Cold feet
  • Weak pulse in the feet (diminished pulsing)
  • Poor feeding

The symptoms of HLHS may look like other medical conditions and heart problems. If you notice any of these signs in your child, it’s important to see a doctor right away.

How is Pediatric Hypoplastic Left Heart Syndrome diagnosed?

Accurate diagnosis of HLHS helps us make sure your child gets the treatment he or she needs as soon as possible – even on their first day of life. 

Prenatal diagnosis (before your child is born):

  • Prenatal screening ultrasounds can show early signs of abnormalities in your child’s heart
  • Specialized testing conducted by fetal heart experts can confirm your child’s diagnosis. Learn more about our fetal heart program.
  • If your child does have HLHS, we help you plan a safe delivery and make sure your child receives treatment immediately after birth

Postnatal diagnosis (after your child is born):

If your child’s condition wasn’t diagnosed before they were born, we provide quick and accurate diagnosis once they start experiencing symptoms with the help of a physical exam and testing.

Your child’s physical exam will include:

  • Questions about growth, development, family history and any recent illnesses
  • Listening to the heart and lungs
  • Observing symptoms

Diagnostic testing will include:

  • Blood tests
  • Chest X-ray
  • Electrocardiogram (EKG)
  • Echocardiogram
  • Tests to check oxygen levels in their blood (pulse oximetry)

The large team of pediatric cardiology specialists at Children's Health includes experts in every aspect of pediatric heart disease, including diagnostic imaging. Learn more about the full range of tests we offer in our cardiac imaging department. 

How is Pediatric Hypoplastic Left Heart Syndrome treated?

Children with HLHS require immediate treatment. At Children’s Health, our goal is to deliver comprehensive care in a compassionate environment that keeps you informed at every decision. Our first step will be to stabilize your child’s heart, which will require a stay in our cardiac intensive care unit. Medications will help stabilize your child until they can have surgery.

All children with HLHS need surgery. You can trust that your child’s care will be in the hands of one of the most experienced pediatric heart surgery teams in the country. We are experts in the most advanced surgical treatments available today. We always recommend the most effective treatment plan for your child’s age and health needs.

These surgeries include:

  • Staged Surgical Treatment: A series of three open-heart procedures that take place in the first few years of life. These procedures result in a more normal blood flow through the lungs and to the body.
    • Norwood procedure: A series of three open-heart procedures taking place in the first three years of life. These procedures increase blood flow to the body by creating a bypass around defective structures in the left heart.
    • Bi-directional Glenn procedure: We create a connection between the pulmonary artery and the vessel returning oxygen-poor blood from the upper part of the body. This allows blood returning from your child's head to flow directly to their lungs.
    • Fontan procedure: Connecting the pulmonary artery with the vessel responsible for returning oxygen-poor blood from the lower part of the body to the heart. This allows the rest of the blood coming back from the body to go to the lungs.
  • Heart transplant: If all other forms of therapy fail to relieve your child’s symptoms, he or she may need a heart transplant.  With over 25 years of experience, we are the most established pediatric heart transplant center in North Texas. Learn more about our heart transplant program.

Our hospital features special operating suites dedicated exclusively to Heart Center patients. These suites include some of the most sophisticated imaging technology available, allowing the experts at Children's Health to perform highly specialized procedures with great precision. Learn more about our cardiothoracic surgery program.  

Pediatric Hypoplastic Left Heart Syndrome Doctors and Providers

Frequently Asked Questions

  • My child was perfectly healthy at birth. How did he or she become so sick?

    Most babies are born with holes in their heart that normally close in the first days of life. When this happens in children with HLHS, blood starts flowing through the defective structures and he or she receives less oxygen, which is why they start showing symptoms.

  • What causes HLHS?

    The cause is unknown. However, if you have one child with HLHS it’s possible that any children you have in the future will be at a greater risk for having it.

  • Will my child’s heart get better on its own?

    No. HLHS creates a life-threatening condition that will not get better on its own. Surgery is the best treatment in all cases.

  • Will my child be able to live a normal life?

    Yes. With proper treatment and regular follow up care, many children with HLHS can expect to live a normal life but he or she may need to take some special precautions to avoid complications.

  • Will my child need surgery later in life?

    It’s possible. Some children with HLHS experience complications such as tiring easily during physical activity and heart rhythm issues (arrhythmias). There are many treatments to help manage these conditions, but sometimes additional surgery is the only way to get lasting relief.


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