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HLHS (Hypoplastic Left Heart Syndrome)

What Is Hypoplastic Left Heart Syndrome (HLHS)?

Hypoplastic Left Heart Syndrome (HLHS) is a congenital heart defect where the left side of the heart is underdeveloped, making it difficult for the heart to pump blood. This congenital heart defect/blood vessel condition occurs during fetal development and is present at birth. Hypoplastic left heart syndrome occurs when the left heart structures are underdeveloped, resulting in a left ventricle that cannot adequately support systemic cardiovascular output. As a result, the patient is left with essentially one functional ventricle (the right ventricle which normally pumps blood out to the lungs) that must be “rerouted and reconfigured” to pump blood to the body. Blood is directed to the lungs by passive flow as opposed to pump flow. This is done through a series of operations throughout the first 2 years of a child’s life.

What Causes Hypoplastic Left Heart Syndrome?

The exact cause of HLHS is often unknown, but certain factors may increase the risk for congenital heart disease, including:

  • Genetic conditions
  • Family history of heart defects
  • Maternal exposures during pregnancy

Early detection through prenatal screenings and diagnostic tests from healthcare professionals is crucial for understanding and managing HLHS.

How Is Hypoplastic Left Heart Syndrome Diagnosed?

HLHS is typically diagnosed during routine prenatal ultrasounds or shortly after birth. Our specialized pediatric cardiology team uses advanced imaging techniques and diagnostic tools to assess and confirm the diagnosis, ensuring a personalized and effective treatment plan. When a baby is not diagnosed during pregnancy, symptoms may develop within the first few hours or days of life. This can include rapid breathing and heartbeat, poor feeding, cold extremities, blue color of the skin, lips, and nailbeds and general weakness. Treatments after birth will focus on stabilizing your baby.

How Is Hypoplastic Left Heart Syndrome Treated?

Treatments for this heart problem can include fetal cardiac intervention, medication, and surgical options like biventricular repair, balloon atrial septostomy, and patent ductus arteriosus (PDA) stenting, a cutting-edge, minimally invasive treatment for babies born with a severe heart condition like HLHS.

Surgical treatment from healthcare professionals involves a series of staged surgical interventions. Our expert pediatric cardiac surgeons work closely with families to explain treatment options for the heart problem/blood flow issues, potential risks, and expected outcomes. These staged heart surgeries aim to reconstruct the heart’s anatomy, allowing for improved blood circulation. These procedures include:

  • Norwood (usually done in the first days of life) – combines the pulmonary artery and aorta to direct flow coming back from the body and lungs back out to the body. An extra connection to the lungs is also made at this time to allow for adequate oxygenation.
  • Bidirectional Glenn (done at 4 to 6 months) – The superior vena cava, which normally returns deoxygenated blood from the head and upper extremities back to the heart, is connected directly to the right pulmonary artery.
  • Fontan (done at 18 months to 2 years) – The inferior vena cava, which returns blood from the lower extremities, liver, and kidneys, is connected via a conduit or baffle to the superior vena cava, which is already connected to the pulmonary arteries. At this point, ALL systemic venous return is going to the lungs, is oxygenated, returned to the pulmonary venous atrium to the single ventricle and out toward the body.

Post-Surgery Care and Follow-Up

After surgical intervention, ongoing care and monitoring are essential to help strengthen the heart and blood vessels. Our dedicated pediatric cardiology team will work with you to create a comprehensive post-surgery care plan. Regular check-ups, diagnostic tests, and therapeutic interventions may be recommended to ensure the best possible outcome for your child’s heart health.

Research and Innovation

As a leading healthcare institution, Rady Children’s actively participates in research and clinical trials aimed at advancing our understanding of HLHS as well as other heart defects and improving treatment outcomes. Our commitment to innovation ensures that your child receives the latest and most effective care available.

Frequently Asked Questions about Hypoplastic Left Heart Syndrome:

  1. What is hypoplastic left heart syndrome?
    Hypoplastic left heart syndrome is a rare congenital heart defect where the left side of the heart is underdeveloped, affecting blood flow through the heart.
  2. What causes hypoplastic left heart syndrome?
    The exact cause is unknown, but it is believed to be due to a combination of genetic and environmental factors.
  3. How is hypoplastic left heart syndrome diagnosed?
    It is usually diagnosed prenatally through fetal echocardiography or after birth with a physical exam and imaging tests.
  4. What are the treatment options for hypoplastic left heart syndrome?
    Treatment typically involves a series of surgeries starting shortly after birth to improve heart function and blood circulation.
  5. What is the prognosis for babies with hypoplastic left heart syndrome?
    The prognosis varies, but with proper treatment, many children can lead active lives, although lifelong monitoring is usually necessary.
  6. Can hypoplastic left heart syndrome be prevented?
    As a congenital condition, it cannot be prevented, but early detection and medical intervention can help manage the condition.
  7. Are there support groups for families of children with hypoplastic left heart syndrome?
    Yes, there are support groups and organizations that provide resources and support for families facing challenges related to this condition.
  8. What are some common complications associated with hypoplastic left heart syndrome?
    Complications can include heart failure, arrhythmias, developmental delays, and issues with the heart valves.
  9. Can hypoplastic left heart syndrome be detected during pregnancy?
    Yes, hypoplastic left heart syndrome can be detected during routine prenatal ultrasounds or through more detailed fetal echocardiography.
  10. Is hypoplastic left heart syndrome curable?
    While there is no cure for hypoplastic left heart syndrome, treatments can help manage symptoms and improve quality of life.