Heart and Blood Conditions

Hypoplastic Left Heart Syndrome

Babies with hypoplastic left heart syndrome need surgery in the first weeks of life. They either get a series of surgeries to redirect blood flow through their heart or they get a  heart transplant .

Before surgery takes place, your baby may need to be on a ventilator, a machine that provides help breathing. Your baby will also need medicine (prostaglandin) that keeps the ductus arteriosus (the blood vessel between the  pulmonary artery  and  aorta ) open so blood can get to the rest of the body.

Hypoplastic left heart syndrome is one of the single-ventricle heart defects because there is only one pumping chamber in the heart. Single-ventricle defects are some of the most complex heart birth defects.

Hypoplastic Left Heart Syndrome Treatment Options


Surgery for this syndrome does not give babies normal circulation. But it may allow their heart to pump blood better to their lungs and the rest of their body.

The surgery is done in three stages during the first few years of life. The first stage, called the Norwood procedure, is usually performed in the first weeks of life and is the most complex. The second stage, called the Glenn operation, is usually performed between 4 and 7 months of age. The last stage, the Fontan procedure, is usually performed around 3 to 4 years of age. The exact procedures and timing depend on your child's condition, including how severe it is.

The goals of the surgeries are:

  • To create a new aorta that can carry enough blood out to the body and to connect this aorta to the right ventricle.
  • To separate oxygen-rich blood from oxygen-poor blood by:
    • Directing oxygen-poor blood, which comes from the organs and tissues of your child's body, to blood vessels that go to their lungs, without going into their heart first. The blood picks up oxygen in the lungs.
    • Allowing oxygen-rich blood, which comes from your child's lungs, to flow into their right ventricle. From there, it can be pumped to the rest of their body.


The heart transplant team at Seattle Children's performs numerous transplants each year for children with this or other heart problems that cannot be controlled using other treatments. Read more about our heart transplant program .

New Treatments for Hypoplastic Left Heart Syndrome

Some babies may be too small or have other medical problems that increase the risk of the first-stage surgery (Norwood procedure) for hypoplastic left heart syndrome. A less complex procedure, called the hybrid procedure , combines surgery and cardiac catheterization. This may be a better option for these higher-risk newborns.

Using a catheter, the cardiologist widens the opening (foramen ovale) between the left and right atria and places a device called a stent in the ductus arteriosus to keep it open. The cardiac surgeon places bands on the pulmonary arteries to control the amount of blood flowing to the lungs. This approach allows the baby to grow and get stronger. During the second stage, the Norwood and Glenn surgeries can be done together with lower risk at 4 to 8 months of age.

Adult Congenital Heart Disease Program

To meet your child's long-term healthcare needs, we have a special Adult Congenital Heart Disease Program to transition your child to adult care when they're ready.