Hypoplastic Left Heart Syndrome
Before you begin reading about this heart defect, please read the explanation of how the normal heart works for a basic understanding of its structure and function.
- What is hypoplastic left heart syndrome?
- What are the symptoms?
- How is it diagnosed?
- What are the treatment options?
- What kind of follow-up care is required?
What is hypoplastic left heart syndrome?
Hypoplastic Left Heart Syndrome
Enlarge+Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect in which the left side of the heart is underdeveloped.
The heart's left side has the job of pumping oxygenated blood into the aorta, the large artery that carries blood to the body. In a child with HLHS:
- The mitral valve, which separates the two left chambers of the heart, is too small or completely closed (atretic).
- The left ventricle (the lower, pumping chamber) is very small.
- The aortic valve, which separates the left ventricle and the aorta, is too small or completely closed (atretic).
Sometimes patients with HLHS also have a ventricular septal defect, a hole between the lower chambers of the heart, or other variations of their cardiac anatomy. In these children, sometimes called "HLHS variants," the treatment strategy is similar to those with the more typical HLHS.
What are the symptoms?
The following symptoms may be present at birth or several days later:
- Blue or purple tint to lips, skin and nails (cyanosis)
- Difficulty breathing
- Difficulty feeding
- Lethargy (sleepy or unresponsive)
How is it diagnosed?
Often HLHS is diagnosed before birth, with fetal echocardiogram (ultrasound). Our Fetal Heart Program will prepare a plan for delivery and care immediately after birth.
Sometimes HLHS is diagnosed hours or days after birth and the baby will need immediate therapy. Diagnosis may require some or all of these tests:
- echocardiogram (also called "echo" or ultrasound) - sound waves create an image of the heart
- electrocardiogram (ECG) - a record of the electrical activity of the heart
- chest X-ray
- pulse oximetry - a non-invasive way to monitor the oxygen content of the blood
- cardiac catheterization - a thin tube is inserted into the heart through a vein and/or artery in either the leg or through the umbilicus ("belly button")
- cardiac MRI - a three-dimensional image shows the heart's abnormalities
Once at The Children's Hospital of Philadelphia, your baby will need intravenous (IV) medicines, and some require a ventilator for help with breathing. Cardiologists and cardiac nurses in our Tabas Cardiac Intensive Care Unit (CICU) will immediately begin procedures to help stabilize the infant.
What are the treatment options?
This condition is most often fatal without early intervention. It will typically require open-heart surgery to re-direct the oxygen-rich ("red") blood and oxygen-poor ("blue") blood in a series of three reconstructive operations known as "Staged Reconstruction."
- Stage I, known as the Norwood procedure, occurs within a few days of birth.
- Stage II, known as the bidirectional Glenn or the hemiFontan, typically occurs within four to six months of birth.
- Stage III, known as the Fontan procedure, typically occurs between one-and-a-half to three years of age.
Frequent surveillance in infancy and early childhood is important to minimize risk factors for the eventual Fontan operation. Your child will also need a customized series of diagnostic tests between the planned stages of surgery, and throughout childhood. Additional surgical or catheter therapies, or in rare cases heart transplantation, may also be recommended.
After these operations:
- The right side of the heart will do what is usually the job of the left side - pumping oxygenated blood to the body.
- The deoxygenated blood will flow from the veins to the lungs without passing through the right side of the heart.
What kind of follow-up care is required?
Through age 18
Children who have had surgical reconstruction for HLHS require life-long care by a cardiologist experienced in congenital heart disease. Sometimes they experience serious health problems. Many remain on medication, and additional surgeries may be required.
Until approximately 25 years ago, infants with HLHS didn't survive. As a result, we don't yet know the truly long-term effects of this condition.
Our pediatric cardiologists follow patients until they are young adults, coordinating care with the primary care physicians.
Into adulthood
We will help older patients with this condition transition to an adult cardiologist.
The Philadelphia Adult Congenital Heart Center, a joint program of The Children's Hospital of Philadelphia and the University of Pennsylvania, meets the unique needs of adults who were born with heart defects.
Because of enormous strides in medicine and technology, today most children with heart conditions go on to lead healthy, productive lives as adults.
Contact the Cardiac Center at The Children's Hospital of Philadelphia for a second opinion or for more information.
Reviewed by: Gil Wernovsky, MD
Date: October 2008
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