Hypoplastic Left Heart Syndrome
Hypoplastic Left Heart Syndrome

Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome is a heart defect that some babies are born with (congenital heart defect). In babies with this defect, the left side of the heart is not completely developed.
The heart is divided into a left side and a right side. The right side receives blood from the body and pumps it to the lungs to pick up oxygen. Then, the oxygen-rich blood goes to the left side of the heart to be pumped back out to the body. In hypoplastic left heart syndrome, several important structures on the left side of the heart are small or missing. This makes it hard for your child's heart to pump enough oxygen-rich blood out to his or her body.
Babies are normally born with openings between the left and right side of the heart (ductus arteriosus and foramen ovale). These openings normally close a few days after birth. In a baby with this syndrome, once the openings close, there is no way for blood to get out to the body.
Problems often seen in children with this syndrome include:
  • A left pumping chamber (left ventricle) that is small or missing.
  • Abnormal valves between the heart and major blood vessels.
  • A hole between the right and left sides of the heart (atrial septal defect).
  • A small aorta.
Surgery is needed to treat this condition. Even after surgery, ongoing follow-up care will be needed throughout your child's life.

What are the causes?

The cause of this condition is not known. It may be due to changes in genes or chromosomes.

What increases the risk?

This condition is more likely to develop in:
  • Boys.
  • Children whose mothers had a low level of folic acid when pregnant.
  • Children whose parents have had a previous child with hypoplastic left heart syndrome.

What are the signs or symptoms?

Symptoms of this condition usually develop within a few hours or days after birth. They include:
  • Trouble breathing.
  • Fast breathing.
  • Weak pulse.
  • Pounding heartbeat.
  • Pale or blue skin.
  • Cold hands and feet.
  • Poor feeding.
  • Lack of strength and energy (lethargy).

How is this diagnosed?

This condition may be found before birth during a routine imaging test called a fetal ultrasound. The diagnosis may be confirmed with a more specific heart ultrasound called a fetal echocardiogram.
After birth, the condition may be diagnosed based on:
  • Symptoms.
  • A physical exam. The health care provider may hear an abnormal heart sound (heart murmur) when listening to your child's heart.
  • An echocardiogram.

How is this treated?

This condition may be treated with a series of three surgeries that aim to improve blood flow from the right side of the heart to your child's body. These surgeries can begin 2 weeks after birth and continue until your child is 3 years old. Most children improve after these surgeries, but they need lifelong care from a heart specialist (cardiologist). Some children may eventually benefit from a heart transplant.
The three surgeries that may be done are:
  • A Norwood procedure. This procedure is done during the first 2 weeks after birth. The procedure makes it easier for the right side of the heart to pump blood to both the lungs and the body.
  • A bidirectional Glenn shunt or hemi-Fontan procedure. This procedure is done when the child is 4–6 months old. After this procedure, blood that returns from the upper body will be able to go straight to the lungs. This reduces the work of the right side of the heart.
  • A Fontan procedure. This procedure is done before 3 years of age. After this procedure, blood that returns from the lower body will be able to go directly to the lungs.
Your child may need to take medicines to stay as healthy as possible before surgery. These include medicines to:
  • Keep the ductus arteriosus from closing.
  • Strengthen the heartbeat.
  • Reduce blood pressure.
  • Keep fluid from building up in the lungs and body.

Follow these instructions at home:

  • Learn as much as you can about your child's condition.
  • Work closely with all of your child's health care providers.
  • Give over-the-counter and prescription medicines only as told by your child's health care provider.
  • Your child may need extra care for feeding and nutrition. For example, your child may need to have a feeding tube for a while, or you may need to feed your child with a higher-calorie formula. Work with your child's nutrition specialist to make sure your child is getting good nutrition.
  • Ask your child's health care provider what level of activity is safe for your child.
  • Keep all follow-up visits as told by your child's health care provider. This is important.

Contact a health care provider if:

  • Your child has a fever.
  • Your child has chills.
  • Your child is not feeding well or not gaining weight.
  • Your child is breathing faster than usual.
  • Your child seems lacking in strength and energy (lethargic).

Get help right away if:

  • Your child who is younger than 3 months has a temperature of 100.4°F (38°C) or higher.
  • Your child's skin turns pale or blue.
  • Your child has trouble breathing.

Summary

  • Hypoplastic left heart syndrome is a heart defect that some babies are born with (congenital heart defect). In babies with this defect, the left side of the heart is not completely developed.
  • Symptoms of this condition usually develop within a few hours or days after birth.
  • Heart surgery is needed to treat this condition.
  • Keep all follow-up visits as told by your child's health care provider. This is important.

This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.