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Pediatric Hypoplastic Left Heart Syndrome (HLHS)

Hypoplastic left heart syndrome occurs when half of the heart doesn’t work the way it should. The Heart Center at Children’s Health is among a select few in the country with a dedicated program for children undergoing treatments for this rare congenital heart disease.

What is Pediatric Hypoplastic Left Heart Syndrome (HLHS)?

Hypoplastic left heart syndrome is a type of single ventricle defect that is present at birth. In a child with hypoplastic left heart syndrome, the left ventricle, a pumping chamber, is too small to pump blood with oxygen to the body. Only the right ventricle (pumping chamber) is able to pump blood to the body. In addition, the first part of the main blood vessel between the heart and the body (aorta) is very small. As a result, your child’s organs and body don’t get the blood and oxygen they need to function properly.

These parts of the left side of the heart are too small or underdeveloped:

  • Left ventricle. The chamber that pumps blood out to the body
  • Mitral valve. The valve that controls blood flow between the two left chambers (atrium and ventricle)
  • Aortic valve. The valve that regulates blood flow from the heart to the rest of the body
  • Aorta. The first part of the large artery arising from the heart

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

  • Pale or blue skin (cyanosis) from low oxygen levels
  • Heavy, rapid breathing
  • Fast heart rate
  • Cold feet
  • Weak pulse throughout the body

An infant with hypoplastic left heart syndrome may appear healthy at first. Symptoms typically appear within the first hours or days of life as oxygen levels and blood circulation drop.

How is Pediatric Hypoplastic Left Heart Syndrome (HLHS) diagnosed?

Doctors at our Fetal Heart Program diagnose hypoplastic left heart syndrome during pregnancy. Sometimes, the condition is caught after birth when your newborn undergoes health screenings that detect low levels of oxygen in the blood.

To make a diagnosis and determine the severity of the heart defects, we use the latest cardiac imaging, including:

What causes Pediatric Hypoplastic Left Heart Syndrome (HLHS)?

Hypoplastic left heart syndrome happens for unknown reasons as a baby develops in the womb. Heart defects aren’t the result of anything a woman does – or doesn’t do – during pregnancy.

How is Pediatric Hypoplastic Left Heart Syndrome (HLHS) treated?

Newborns with hypoplastic left heart syndrome need immediate care soon after birth. We partner with your maternity hospital to start therapies and quickly bring your baby to our pediatric cardiac intensive care unit (CICU). Here, your baby is in the expert hands of a pediatric heart team with deep experience treating this uncommon heart condition.

Our surgical treatments provide a different way for your child’s heart to circulate blood, ensuring their body gets the oxygen it needs. But even after these surgeries, your child will always have just one working pumping chamber.

Treatment for hypoplastic left heart syndrome involves a series of three separate open-heart surgeries:

  • Norwood procedure. Soon after birth, our heart surgeons reconstruct the aorta so that blood flows from the heart to the body. We also create a pathway for blood to flow to the lungs to get oxygen.
  • Glenn procedure. When your baby is 4 to 6 months old, our heart surgeons make a connection between the superior vena cava (a large blood vessel) and blood vessels in the lungs. This allows blood from the upper body to reach the lungs to get oxygen.
  • Fontan procedure. When your child is 18 to 36 months of age, our heart surgeons make a connection to bring blood flow from the lower body to the pulmonary artery in the heart. After this procedure, all blood in the body goes directly to the lungs for oxygen without passing through the heart.

Children’s Health℠ is among a select few pediatric hospitals in the country with a dedicated Fontan Program for children with hypoplastic left heart syndrome. We offer all the care your child needs to enjoy their healthiest life possible.

Pediatric Hypoplastic Left Heart Syndrome (HLHS) Doctors and Providers

As experts in hypoplastic left heart syndrome, our team is well-positioned to guide you and your child through the various surgeries and to care for your child later in life.

Frequently Asked Questions

  • How common is hypoplastic left heart syndrome?

    Hypoplastic left heart syndrome is a very rare heart defect. It occurs in about 1,000 newborns in the U.S. every year.

  • What type of follow-up care does my child need?

    Your child needs lifelong monitoring by a cardiologist. When they become an adult, they can transition to our Adult Congenital Heart Disease Program. A child with hypoplastic left heart syndrome is at risk for developing an arrhythmia (abnormal heart rhythm), leaky heart valves or other heart problems that require treatment.

  • Will my child have an active life?

    Even after surgery, your child only has half of a working heart. Your child’s exercise capacity will be about two-thirds of normal levels. Although some physical activities may be safe, it’s best to follow the advice of your child’s cardiologist. Most children need to limit involvement in contact sports or other strenuous physical activities.