Before birth

It's possible for a baby to be diagnosed with hypoplastic left heart syndrome while it's still in the womb. Your doctor may be able to identify the condition on a routine ultrasound exam during the second trimester of pregnancy.

After birth

After your baby is born, his or her doctor may suspect a heart defect, such as hypoplastic left heart syndrome, if your baby has grayish-blue skin color or has trouble breathing. Your baby's doctor may also suspect a heart defect if he or she hears a heart murmur when listening to the heart with a stethoscope — an abnormal whooshing sound caused by turbulent blood flow.

Doctors usually use an echocardiogram to diagnose hypoplastic left heart syndrome. This test uses high-pitched sound waves that bounce off your baby's heart to produce moving images that can be viewed on a video screen.

If your baby has hypoplastic left heart syndrome, the echocardiogram will show a smaller than normal left ventricle and aorta. The echocardiogram may also show abnormal heart valves.

Because this test can track blood flow, it also shows blood moving from the right ventricle into the aorta. In addition, an echocardiogram can identify associated heart defects, such as an atrial septal defect.


Hypoplastic left heart syndrome is treated through several surgical procedures or a heart transplant. Your doctor will discuss with you the treatment options for your child.

If the diagnosis has been made before the baby is born, doctors usually recommend delivery at a hospital with a cardiac surgery center.

Before surgery

Your baby's doctor may recommend several options to help manage your baby's condition before surgery or transplant. They may include:

  • Medication. The medication alprostadil (Prostin VR Pediatric) helps dilate the blood vessels and keeps the ductus arteriosus open.
  • Breathing assistance. If your baby has trouble breathing, he or she may need help from a breathing machine (ventilator), which ensures adequate oxygen delivery.
  • Intravenous fluids. Your baby will receive fluids through a tube inserted into a vein.
  • Feeding tube. If your baby has trouble or gets tired while feeding, he or she may be fed through a feeding tube.
  • Atrial septostomy. This procedure creates or enlarges the opening between the heart's upper chambers (atria) to allow more blood flow between the right atrium to the left atrium if the foramen ovale closes or is too small. If your baby already has an atrial septal defect, an atrial septostomy may not be necessary.


Your child will likely need several surgical procedures to treat hypoplastic left heart syndrome. Surgeons perform these procedures in three stages. These procedures are designed to create normal blood flow in and out of the heart so the body gets the oxygen-rich blood it needs.

  • Norwood procedure. This surgery is usually performed within the first two weeks of your child's life. Several forms of this procedure may be performed.

    Surgeons reconstruct the aorta and connect it directly to the heart's lower right chamber (right ventricle). Surgeons insert a tube (shunt) that connects the aorta to the arteries leading to the lungs (pulmonary arteries), or they place a shunt that connects the right ventricle to the pulmonary arteries. This procedure allows the right ventricle to effectively pump blood to both the lungs and the body.

    In some cases, doctors may perform a hybrid procedure. Surgeons implant a stent in the ductus arteriosus to maintain the opening between the pulmonary artery and aorta, place bands around the pulmonary arteries to reduce blood flow to the lungs, and create an opening between the atria of the heart.

    After this procedure, your baby's skin will still have a blue cast because oxygen-rich blood and oxygen-poor blood continue to mix within the heart. Once your baby successfully passes through this stage of treatment, the odds of survival may increase, but he or she may still be at risk of death due to complications.

  • Bi-directional Glenn procedure. This procedure is generally the second operation and is performed when your child is between 3 and 6 months of age. In this procedure, doctors remove the first shunt attached to the pulmonary arteries, and then connect one of the large veins that normally returns blood to the heart (the superior vena cava) to the pulmonary artery instead. If surgeons previously performed a hybrid procedure, they'll conduct additional steps during this procedure.

    This procedure reduces the work of the right ventricle by allowing it to pump blood mainly to the aorta. It also allows most of the oxygen-poor blood returning from the body to flow directly into the lungs without a pump.

    After this procedure, all the blood returning from the upper body is sent to the lungs, so blood with more oxygen is pumped to the aorta to supply organs and tissues throughout the body.

  • Fontan procedure. This procedure is usually performed when your child is between 18 months and 4 years of age. During this procedure, the surgeon creates a path for the oxygen-poor blood in one of the blood vessels that returns blood to the heart (the inferior vena cava) to flow directly into the pulmonary arteries. The pulmonary arteries then transport the blood into the lungs.

    This procedure allows the rest of the oxygen-poor blood returning from the body to flow to the lungs. After this procedure, there's no mixing of oxygen-rich and oxygen-poor blood in the heart, and your child's skin will no longer look blue.

Another surgical option is a heart transplant, especially when the associated heart defects are complex. Babies with hypoplastic left heart syndrome can be considered for a transplant. After a heart transplant, your child will need lifelong medications to prevent the body from rejecting the donor heart.

Follow-up care

After surgery or a transplant, your baby will need lifelong follow-up care with a cardiologist trained in congenital heart diseases to monitor his or her heart health. Some medications may be necessary to regulate heart function. Various complications may occur over time and may require further treatment or medications.

Your child's cardiologist will tell you whether your child needs to take preventive antibiotics before certain dental or other procedures to prevent infections. In some cases, he or she may also recommend that your child limit physical activity.

Follow-up care for adults

As an adult, you'll transition from a pediatric cardiologist to a cardiologist trained in congenital heart disease in adults. It's only recently that advances in surgical care have resulted in children with hypoplastic left heart syndrome surviving into adulthood, so it's not yet clear the exact challenges an adult with the condition may face. That's why you'll need regular, lifelong follow-up care to monitor for any changes in your condition.

If you're a woman and you're considering pregnancy, discuss pregnancy risks and birth control options with your doctor. Pregnancy typically isn't recommended for someone with hypoplastic left heart syndrome.

However, some women with the condition have had healthy pregnancies and deliveries. But, during pregnancy, such a woman's risk of cardiovascular problems is higher than it is for a woman without hypoplastic left heart syndrome. The risk of having a baby with congenital heart disease is also increased if the mother has congenital heart disease.

Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this disease.

Coping and support

It can be challenging to live with hypoplastic left heart syndrome or to care for a baby with the condition. Here are some strategies that may help make it easier:

  • Seek support. If you have a child with hypoplastic left heart syndrome, ask for help from family members and friends. It's important for caregivers to take breaks sometimes. Talk with your child's cardiologist about support groups and other types of assistance that are available near you.

    If you're a teen or an adult with hypoplastic left heart syndrome, ask your doctor if there are any support groups for adults with congenital heart conditions. It can be helpful to talk to other people who understand your challenges and triumphs.

  • Record your baby's health history. It's important to write down your or your baby's diagnosis, medications, surgery and other procedures and the dates they were performed, as well as the name and phone number of your or your child's cardiologist, emergency contact numbers for your or your child's doctors and hospital, and any other important information about your or your baby's care. It's also important to include a copy of the operative report from your or your child's surgeon in your records.

    This information will help you recall the care you or your child has received, and it will be useful for doctors who are unfamiliar with you or your baby to review your or your child's complex health history. This information is also helpful as your child grows into adulthood and transitions from pediatric to adult cardiology care.

  • Talk about your concerns. As your child grows, you may worry about activities in which he or she can safely participate. Talk with the cardiologist about which activities are best for your child. If some are off-limits, encourage your child in other pursuits rather than focusing on what he or she can't do. If other issues about your child's health concern you, discuss them with your child's cardiologist, too. As an adult, ask your doctor about what activities you can do, and if you have any questions or concerns.

Hypoplastic left heart syndrome care at Mayo Clinic

Aug. 04, 2018
  1. Rathod RH. Hypoplastic left heart syndrome: Anatomy, clinical features, and diagnosis. https://www.uptodate.com/contents/search. Accessed June 17, 2018.
  2. Mussa S, et al. Hypoplastic left heart syndrome. Paediatrics and Child Health. 2016;27:75.
  3. Bonow RO, et al., eds. Congenital heart disease in the adult and pediatric patient. In: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 11th ed. Philadelphia, Pa.: Saunders Elsevier; 2019. https://www.clinicalkey.com. Accessed June 16, 2018.
  4. Facts about hypoplastic left heart syndrome. Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/heartdefects/HLHS.html. Accessed June 17, 2018.
  5. Single ventricle defects. American Heart Association. http://www.heart.org/HEARTORG/Conditions/CongenitalHeartDefects/AboutCongenitalHeartDefects/Single-Ventricle-Defects_UCM_307037_Article.jsp#.Wyc5u4onZEY. Accessed June 17, 2018.
  6. Rathod RH. Hypoplastic left heart syndrome: Management and outcome. https://www.uptodate.com/contents/search. Accessed June 17, 2018.
  7. Waltzman M. Initial evaluation of shock in children. https://www.uptodate.com/contents/search. Accessed June 17, 2018.
  8. Ohye RG, et al. Current therapy for hypoplastic left heart syndrome and related single ventricle lesions. Circulation. 2016;134:1265.
  9. What are congenital heart defects? National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health-topics/congenital-heart-defects. Accessed June 17, 2018.
  10. Collins II RT, et al. National in-hospital outcomes of pregnancy in women with single ventricle congenital heart disease. American Journal of Cardiology. 2017;119:1106.
  11. Riggin EA. Allscripts EPSi. Mayo Clinic, Rochester, Minn. March 13, 2018.