Health Information

Hypoplastic Left Heart Syndrome


Hypoplastic left heart syndrome is a rare heart defect. In a normal heart, the blood flows in from the body to the right atrium. It then goes into the right ventricle. Next, the blood travels to the lungs through the pulmonary valve. Here, it picks up fresh oxygen. The blood returns to the left atrium and goes into the left ventricle. The blood then moves out to the rest of the body.

With this syndrome, structures on the left side of the heart, which includes the aorta, aortic valve, left ventricle, and mitral valve, may be:

  • Too small
  • Absent
  • Abnormally developed

Since the heart cannot function properly, oxygen-rich blood flow to the body is limited. This condition requires immediate care from a doctor.

Heart Chambers and Valves
heart anatomy
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Blood Flow Through the Heart
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This is a congenital heart defect. This means that the heart forms incorrectly when the baby develops in the womb. The baby is born with the condition. It is not known why the heart forms this way.

Risk Factors

These factors increase your chance of having a child with hypoplastic left heart syndrome:

  • Previous pregnancy with fetal heart abnormalities or fetal loss
  • Family history of congenital heart defect


Symptoms usually appear within days after birth. Tell the doctor if you notice the following in your infant or child:

  • Blue/gray skin color
  • Cool skin
  • Rapid or difficult breathing
  • High heart rate
  • Sweaty, clammy skin
  • Poor feeding


The doctor will ask about your child's symptoms and medical history. A physical exam will be done.

Images may be taken of your child's chest. This can be done with:

Other tests may be done to evaluate your child's heart. This can be done with:


Talk with your doctor about the best treatment plan for your child. Some defects may be so severe that they are difficult to treat. Treatment options include:


Medications, such as Prostaglandin E1, are necessary to keep blood flowing through the ductus arteriosus. The ductus arteriosus is a connection between the pulmonary artery and the aorta, which is the largest artery in the body. It usually closes within a few days after birth. Keeping this passage open is a temporary treatment. Other medicines may be used as well.


Sometimes a shunt can be placed between the aorta and pulmonary artery. This is done to improve blood flow. Treatment will include more surgeries, which are usually done in stages:

  • After birth
  • 4-6 months of age
  • 2-4 years of age

In addition to the shunt procedure, the initial surgery may also create a connection between the aorta and the right ventricle. This is done so that the right ventricle pushes blood to both the lungs and the rest of the body. This is called a Norwood Procedure. As the child ages, more surgeries will be needed to create other connections with the heart, lungs, and body. In some cases, a heart transplant may be needed.

Lifelong Monitoring

Your child will need to see a heart specialist regularly. Heart medicine will be needed throughout your child's life.


There is no way to prevent this condition. Getting appropriate prenatal care is always important.

Revision Information

  • - American Academy of Family Physicians

  • American Heart Association

  • Canadian Cardiovascular Society

  • Heart and Stroke Foundation of Canada

  • Hypoplastic left heart syndrome. American Heart Association website. Available at: Updated January 8, 2013. Accessed July 18, 2013.

  • Hypoplastic left heart syndrome. Children’s Hospital Boston website. Available at: Accessed July 18, 2013.

  • Hypoplastic left heart syndrome. EBSCO DynaMed website. Available at: Updated June 27, 2013. Accessed July 18, 2013.

  • Hypoplastic left heart syndrome. Johns Hopkins University, Cove Point Foundation website. Available at: Updated May 16, 2011. Accessed July 18, 2013.