Hypoplastic left heart syndrome (HLHS) is an abnormality of the heart that a baby is born with. The left side of the heart is smaller and weaker than it should be. HLHS surgery is required to create new pathways for the heart to pump oxygen-rich blood through the body.

Since the left side of the newborn’s heart doesn’t pump enough blood, the right side of the heart has to work harder but won’t be getting enough oxygen from the lungs.

A baby born with HLHS often has an atrial septal defect (ASD) — a hole between the ventricles that actually helps their heart function. The hole allows oxygenated blood from the left ventricle mix with the blood being pumped out to their body.

Babies born with HLHS but without this hole will need an emergency intervention called a balloon septostomy shortly after birth to create such a hole.

Another hole — the patent ductus arteriosus (PDA) — is normal and usually closes within the first few days of life. In a baby with HLHS, this hole also helps mix the oxygenated blood and needs to be kept open. Prostaglandin is a medication frequently given to babies with HLHS after birth to keep the PDA open. The cardiothoracic surgeons at Norton Children’s Heart Institute, affiliated with the UofL School of Medicine, are prepared and experienced to act swiftly to keep the PDA and the ASD open until the heart is repaired with HLHS surgery.

It wasn’t long ago that babies born with HLHS didn’t survive. Using the latest techniques, the board-certified and fellowship-trained specialists at Norton Children’s Heart Institute have the skills and experience to effectively rebuild a baby’s circulatory system with HLHS surgery, helping them to potentially live a full and productive life.

Hypoplastic Left Heart Syndrome Diagnosis

HLHS may be seen on ultrasound scans during pregnancy. A fetal echocardiogram provides more information and tells the delivery team how to prepare for care after birth.

Common tests used to learn more about a newborn’s heart include:

• Echocardiogram (ultrasound images and videos of the heart)
• Chest X-ray, an image of the heart and surrounding organs
• Electrocardiogram (ECG or EKG), a recording of the heart’s electrical activity
• Pulse oximetry (measuring the oxygen in blood on a fingertip or toe)

HLHS Surgery

HLHS most often is diagnosed through ultrasound before the baby’s birth. The cardiothoracic surgeons at Norton Children’s Heart Institute are poised to stabilize the newborn immediately while more diagnostic tests are performed.

In addition to administering prostaglandin to keep the PDA open, doctors will use medications and mechanical ventilation strategies (breathing assistance) to balance blood flow to the lungs and the rest of the body.

HLHS surgery may involve a series of three surgeries. In some cases, a child with hypoplastic left heart syndrome may need a heart transplant because the case is so complex or because the heart becomes weak after HLHS surgery.

Norwood Procedure

• The Norwood procedure is done in the first or second week of a baby’s life to allow the right ventricle do the work of the left ventricle — pumping blood to the body — and its normal job of pumping deoxygenated blood returning to the heart back to the lungs.
• To create this new single-ventricle blood flow, cardiothoracic surgeons create a new aorta to connect to the right ventricle so it can take over the left ventricle’s job pumping oxygen-rich blood to the body.
• A tube is placed from either the large arteries off the aorta or the right ventricle and connected to the blood vessels supplying the lungs, also known as the pulmonary arteries, so the blood can pick up fresh oxygen.
• The right ventricle is then able to pump blood to both the lungs and the rest of the body.
• Once stable, the baby will go home while they grow and build strength for the next procedure in a few months. The family is given a specially equipped iPad and other tools to monitor the baby’s condition and send data at least daily to the team at Norton Children’s Heart Institute. This allows providers to react quickly when a child’s condition changes — sometimes even before the parents realize something is wrong.

Glenn Procedure

• The Glenn procedure typically is performed when the infant is 4 to 6 months old and is a step toward allowing the right ventricle to perform just the work of the left ventricle, pumping blood to the body.
• The Glenn procedure allows blood returning from the upper part of the body to go directly into the lungs, bypassing the right ventricle. Cardiothoracic surgeons create a direct connection between the pulmonary artery and the superior vena cava, the blood vessel that returns oxygen-poor blood from the upper part of the body to the heart.
• The procedure reduces the work of the right ventricle by removing the burden of handling blood returning from the upper part of the body. Blood returning from the lower part of the body still goes through the right ventricle at this point.

Fontan Procedure

• The Fontan procedure typically is performed when the child is 2 to 4 years old to reroute blood from the lower part of the body directly to the lungs and allow the right ventricle to replace the left ventricle.
• Cardiothoracic surgeons connect the pulmonary artery and the inferior vena cava, diverting oxygen-poor blood from the lower part of the body directly to the lungs.
• This procedure allows the rest of the blood coming back from the body to go to the lungs.
• Once this procedure is complete, oxygen-rich and oxygen-poor blood will no longer mix in the heart, and the child’s skin will no longer look bluish.
• Some patients will have a “fenestration” (opening) connecting the venous and arterial circulations, which allows mixing to periodically occur.
• These surgeries don’t cure HLHS. The child will need regular follow-up visits with a pediatric cardiologist to monitor progress. When the child becomes an adult, they will need to see an adult congenital heart disease (ACHD) specialist for lifelong care.

Fontan Clinic

Growing into adulthood with this unique single-ventricle circulatory system can come with complications and risks affecting the liver, kidneys, heart or lungs.

The Norton Children’s Heart Institute Fontan Clinic provides regular follow-up and monitoring to help spot any emerging issue early and treat it sooner, when more options may be available.

The clinic works in conjunction with the Norton Children’s Heart Institute’s adult congenital heart disease program to provide sophisticated care to patients born with heart conditions.

Why Choose Norton Children’s Heart Institute

• Norton Children’s Hospital has been a pioneer in pediatric cardiothoracic surgery, performing Kentucky’s first pediatric heart transplant in 1986 and becoming the second site in the United States to perform an infant heart transplant.
• The American Board of Thoracic Surgery has certified our cardiothoracic surgeons in congenital heart surgery.
• The Adult Congenital Heart Association has accredited Norton Children’s Heart Adult Congenital Heart Disease Program as the only comprehensive care center in Kentucky and Indiana treating adults born with a heart defect.
• More than 17,000 children a year visit Norton Children’s Heart Institute for advanced heart care.
• Norton Children’s Heart Institute has offices across Kentucky and Southern Indiana to bring quality pediatric heart care closer to home.
• The Jennifer Lawrence Cardiac Intensive Care Unit (CICU) at Norton Children’s Hospital is the largest dedicated CICU in Kentucky, equipped with 17 private rooms and the newest technology available for heart care.