Hypoplastic Left Heart Syndrome

An introduction to the Symptoms, Diagnosis and Treatment for Hypoplastic Left Heart Syndrome

Overview

Hypoplastic left heart syndrome is a complex and rare heart defect present at birth (congenital). The left side of the heart is critically underdeveloped in hypoplastic left heart syndrome.

If your baby is born with hypoplastic left heart syndrome, the left side of the heart can’t effectively pump blood to the body. Instead, the right side of the heart must pump blood to the lungs and to the rest of the body.

Medication to prevent closure of the connection (ductus arteriosus) between the right and left sides, followed by either surgery or a heart transplant, is necessary to treat hypoplastic left heart syndrome.

With advances in care, the outlook for babies born with hypoplastic left heart syndrome is better now than in the past. All people who are born with hypoplastic left heart syndrome will have undergone multiple complex cardiac surgeries and require lifelong follow up by a specialist congenital heart expert.

Hypoplastic Left Heart Syndrome

Symptoms

Babies born with hypoplastic left heart syndrome usually are seriously ill soon after birth. Hypoplastic left heart syndrome symptoms include:

  • Grayish-blue skin colour (cyanosis)
  • Rapid, difficult breathing
  • Poor feeding
  • Cold hands and feet
  • Weak pulse
  • Being unusually drowsy or inactive

Diagnosis

Before birth

It’s possible for a baby to be diagnosed with hypoplastic left heart syndrome while it’s still in the womb. Your doctor may be able to identify the condition on a routine ultrasound exam during the second trimester of pregnancy.

After birth

After your baby is born, the doctor may suspect a heart defect, such as hypoplastic left heart syndrome, if your baby has grayish-blue skin color or has trouble breathing. Your baby’s doctor may also suspect a heart defect if he or she hears a heart murmur when listening to the heart with a stethoscope — an abnormal whooshing sound caused by turbulent blood flow.

Doctors usually use an echocardiogram to diagnose hypoplastic left heart syndrome. This test uses high-pitched sound waves that bounce off your baby’s heart to produce moving images that can be viewed on a video screen. If your baby has hypoplastic left heart syndrome, the echocardiogram will show a smaller than normal left ventricle and aorta. The echocardiogram may also show abnormal heart valves.

Treatment

Hypoplastic left heart syndrome is treated through several surgical procedures or a heart transplant. Your doctor will discuss with you the treatment options for your child.

If the diagnosis has been made before the baby is born, doctors usually recommend delivery at a hospital with a cardiac surgery centre.

Before surgery

Your baby’s doctor may recommend several options to help manage your baby’s condition before surgery or transplant. They may include:

  • Medication: A medication called Prostaglandin E1 helps dilate the blood vessels and keeps the ductus arteriosus open.
  • Atrial septostomy: This procedure creates or enlarges the opening between the heart’s upper chambers (atria) to allow more blood flow between the right atrium to the left atrium if the foramen ovale closes or is too small. If your baby already has an atrial septal defect, an atrial septostomy may not be necessary.

Surgery

Your child will likely need several surgical procedures to treat hypoplastic left heart syndrome. Surgeons usually perform these procedures in three stages. These procedures are designed to create normal blood flow in and out of the heart so the body gets the oxygen-rich blood it needs. However, they cannot cure the underlying heart condition, and so are known as ‘palliative surgeries’.

  • Norwood procedure: This surgery is usually performed within the first two weeks of your child’s life. Several forms of this procedure may be performed. Surgeons reconstruct the aorta and connect it directly to the heart’s lower right chamber (right ventricle). Surgeons insert a tube (shunt) that connects the aorta to the arteries leading to the lungs (pulmonary arteries), or they place a shunt that connects the right ventricle to the pulmonary arteries. This procedure allows the right ventricle to effectively pump blood to both the lungs and the body. In some cases, doctors may perform a hybrid procedure. Surgeons implant a stent in the ductus arteriosus to maintain the opening between the pulmonary artery and aorta, place bands around the pulmonary arteries to reduce blood flow to the lungs and create an opening between the atria of the heart.

After this procedure, your baby’s skin will still have a blue cast because oxygen-rich blood and oxygen-poor blood continue to mix within the heart. Once your baby successfully passes through this stage of treatment, the odds of survival may increase, but he or she may still be at risk of death due to complications.

  • Bi-directional Glenn procedure: This procedure is generally the second operation and is performed when your child is between 3 and 6 months of age. In this procedure, doctors remove the first shunt attached to the pulmonary arteries, and then connect one of the large veins that normally returns blood to the heart (the superior vena cava) to the pulmonary artery instead. If surgeons previously performed a hybrid procedure, they’ll conduct additional steps during this procedure.

This procedure reduces the work of the right ventricle by allowing it to pump blood mainly to the aorta. It also allows most of the oxygen-poor blood returning from the body to flow directly into the lungs without a pump. After this procedure, all the blood returning from the upper body is sent to the lungs, so blood with more oxygen is pumped to the aorta to supply organs and tissues throughout the body.

  • Fontan procedure: This procedure is usually performed when your child is between 18 months and 4 years of age. During this procedure, the surgeon creates a path for the oxygen-poor blood in one of the blood vessels that returns blood to the heart (the inferior vena cava) to flow directly into the pulmonary arteries. The pulmonary arteries then transport the blood into the lungs. This procedure allows the rest of the oxygen-poor blood returning from the body to flow to the lungs. After this procedure, there’s no mixing of oxygen-rich and oxygen-poor blood in the heart, and your child’s skin will no longer look blue.

Another surgical option is a heart transplant, especially when the associated heart defects are complex. Babies with hypoplastic left heart syndrome can be considered for a transplant. A transplant is also considered for adult patients who have developed complications, despite undergoing surgical palliation.

Follow-up Care

After surgery, your baby will need lifelong follow-up care with a cardiologist trained in congenital heart diseases to monitor his or her heart health. Various complications may occur over time and may require further treatment or medications.

Your child’s cardiologist will tell you whether your child needs to take medications to aid heart function and/or antibiotics before certain dental or other procedures to prevent infections. In some cases, he or she may also recommend that your child limit physical activity.

Follow-up care for adults

As an adult, you’ll transition from a paediatric cardiologist to a cardiologist trained in congenital heart disease in adults. It’s only recently that advances in surgical care have resulted in children with hypoplastic left heart syndrome surviving into adulthood, so it’s not yet clear the exact challenges an adult with the condition may face.

Some of the possible complications that may arise are abnormal heart rhythms, poor/decreasing pump function of the heart, clotting events (clot in lung, fontan system or stroke), decreasing exercise capacity or abnormal protein loss from the body (protein losing enteropathy).

Adults may require repeat interventions and multiple medications to help manage complications. Cardiac transplantation may be recommended for some people.

Lifelong regular follow-up care to monitor for any changes in heat function or for any complications is necessary for all patients with this condition. At the Irish Congenital Heart Centre, our specialists are experienced in managing people with this condition. We aim to identify and manage any complications as promptly as possible.

Conditions We Treat

Pulmonary Valve Stenosis

Pulmonary valve stenosis is a condition in which a deformity on or near your pulmonary valve narrows the pulmonary valve opening and slows the blood flow. The pulmonary valve is located between the lower right heart chamber (right ventricle) and the pulmonary arteries. Adults occasionally have pulmonary valve stenosis as a complication of another illness, but mostly, pulmonary valve stenosis develops before birth as a congenital heart defect. Pulmonary valve stenosis ranges from mild to severe. Mild pulmonary stenosis doesn't usually worsen over time, but moderate and severe cases may worsen and require surgery. Fortunately, treatment is generally highly successful, and most people with pulmonary valve stenosis can expect to lead normal lives. Find Out More >>

Patent Foramen Ovale

A patent foramen ovale (PFO) is a hole in the heart that didn't close the way it should have after birth. During fetal development, a small flap-like opening — the foramen ovale — is present in the wall between the right and left upper chambers of the heart (atria). It normally closes during infancy. When the foramen ovale doesn't close, it's called a patent foramen ovale. Patent foramen ovale occurs in about 25% of the normal population, but most people with the condition never know they have it. Learning that you have a patent foramen ovale is understandably concerning, but most people never need treatment for this condition. A patent foramen ovale is often discovered during tests for other problems. In certain conditions, such as unexplained strokes (cryptogenic stroke) in young people, closure might be recommended by your doctor. Find Out More >>

Tetralogy of Fallot

Tetralogy of Fallot is a rare condition caused by a combination of four heart defects that are present at birth (congenital). These defects, which affect the structure of the heart, cause oxygen-poor blood to flow out of the heart and to the rest of the body. Tetralogy of Fallot is usually diagnosed during infancy or soon after. However, it might not be detected until later in life in some adults, depending on the severity of the defects and symptoms. With early diagnosis followed by appropriate surgical treatment, most people who have Tetralogy of Fallot live relatively normal lives. Many adults with repaired Tetralogy of Fallot will require another procedure or intervention during their lifetimes. It is important to have regular follow-up with a cardiologist trained in congenital heart disease who can evaluate you and determine the appropriate timing of another intervention or procedure. At the Irish Congenital Heart Centre, our specialists have trained in congenital heart disease and are expert at caring for people with Tetralogy of Fallot. Find Out More >>

Partial Anomalous Pulmonary Venous Return

Partial anomalous pulmonary venous return, sometimes called partial anomalous pulmonary venous connection, is a heart defect present at birth (congenital) in which some of the pulmonary veins carrying blood from the lungs to the heart flow into other blood vessels or into the heart's upper right chamber (right atrium), instead of correctly entering the heart's upper left chamber (left atrium). This causes some oxygen-rich blood from the lungs to mix with oxygen-poor blood before entering the right atrium. Some people with this defect also have a hole between the upper heart chambers (atrial septal defect), which allows blood to flow between the upper heart chambers (atria). People with this condition may also have other congenital heart defects. Find Out More >>

Ebstein Anomaly

Ebstein anomaly is a rare heart defect that's present at birth (congenital). In Ebstein anomaly, your tricuspid valve — the valve between the two right heart chambers (right atrium and right ventricle) — doesn't work properly. The tricuspid valve sits lower than normal in the right ventricle, and the tricuspid valve's leaflets are abnormally formed. Blood may leak back through the valve, making your heart work less efficiently. Ebstein anomaly may also lead to enlargement of the heart or heart failure. A significant proportion of people with Ebstein anomaly will also have a communication between the top two chambers of the heart - an atrial septal defect (ASD). Abnormal electrical activity of the heart, leading to abnormal heartbeats (arrhythmia) is also a common problem for people with Ebstein anomaly. If you have no signs or symptoms associated with Ebstein anomaly, careful monitoring of your heart may be all that's necessary. If signs and symptoms bother you, or if the heart is enlarging or becoming weaker, treatment for Ebstein anomaly may be necessary. Treatment options include medications and surgery. Find Out More >>

Atrial Septal Defect

An atrial septal defect (ASD) is a hole in the wall between the two upper chambers of your heart (atria). The condition is present at birth (congenital). Small defects may never cause a problem and may be found incidentally. It's also possible that small atrial septal defects may close on their own during infancy or early childhood. Large and long-standing atrial septal defects can damage your heart and lungs. An adult who has had an undetected atrial septal defect for decades may have a shortened life span from heart failure or high blood pressure that affects the arteries in the lungs (pulmonary hypertension). Surgery may be necessary to repair atrial septal defects to prevent complications. Find Out More >>

Atrioventricular Canal Defect

Atrioventricular canal defect is a combination of heart problems resulting in a defect in the centre of the heart. The condition occurs when there's a hole between the heart's chambers and problems with the valves that regulate blood flow in the heart. Sometimes called endocardial cushion defect or atrioventricular septal defect, atrioventricular canal defect is present at birth (congenital). The condition is often associated with Down Syndrome. Atrioventricular canal defect allows extra blood to flow to the lungs. The extra blood forces the heart to overwork, causing the heart muscle to enlarge. Untreated, atrioventricular canal defect can cause heart failure and high blood pressure in the lungs. Doctors generally recommend surgery during the first year of life to close the hole in the heart and to reconstruct the valves. Find Out More >>

Bicuspid Aortic Valve

Bicuspid aortic valve is the commonest form of congenital heart disease. Approximately 1% of the population are born with this condition. A bicuspid aortic valve is an aortic valve that has only two leafelts (bicuspid) instead of the normal three leaflets (tricuspid) . Some people may also be born with one (unicuspid) or four (quadricuspid) leaflets, but these are rare. A bicuspid aortic valve may cause the heart's aortic valve to narrow (aortic valve stenosis). This narrowing prevents the valve from opening fully, which reduces or blocks blood flow from the heart to the body. In some cases, the bicuspid aortic valve doesn't close efficiently, causing blood to leak backward into the left ventricle (aortic valve regurgitation). Some people with a bicuspid aortic valve may develop an enlarged aorta — the main blood vessel leading from the heart (see also  our Aortopathy section) Most people with a bicuspid aortic valve aren't affected by valve problems until they are adults, and some may not be affected until they are older adults. However if you are known to have a biscupid aortic valve, you should be followed up by a cardiologist at regular intervals. Find Out More >>

Coarctation of the Aorta

Coarctation of the aorta — or aortic coarctation — is a narrowing of the aorta, the large blood vessel that branches off your heart and delivers oxygen-rich blood to your body. When this occurs, your heart must pump harder to force blood through the narrowed part of your aorta. Coarctation of the aorta is generally present at birth (congenital). The condition can range from mild to severe, and might not be detected until adulthood, depending on how narrowed the aorta is. Coarctation of the aorta often occurs along with other heart defects. While treatment is usually successful, the condition requires careful lifelong follow-up. Find Out More >>

Ventricular Septal Defect

A ventricular septal defect (VSD) is a type of hole in the heart. It is present at birth (congenital). The hole (defect) occurs in the wall (septum) that separates the heart's lower chambers (ventricles) and allows blood to pass from the left to the right side of the heart. This means that oxygen-rich blood then gets pumped back to the lungs instead of out to the body, causing the heart to work harder. A small ventricular septal defect may cause no problems, and many small VSDs close on their own. Medium or larger VSDs may need surgical repair early in life to prevent complications. Find Out More >>

Transposition of the Great Arteries

Transposition of the great arteries is a serious but rare heart defect present at birth (congenital), in which the two main arteries leaving the heart are reversed (transposed). The condition is also called dextro-transposition of the great arteries. A rarer type of this condition is called levo-transposition of the great arteries. Transposition of the great arteries changes the way blood circulates through the body, leaving a shortage of oxygen in blood flowing from the heart to the rest of the body. Without an adequate supply of oxygen-rich blood, the body can't function properly and your child faces serious complications or death without treatment. Transposition of the great arteries is usually detected either prenatally or within the first hours to weeks of life. Corrective surgery soon after birth is the usual treatment for transposition of the great arteries, and with proper treatment, the outlook is promising. Even when this condition is diagnosed and treated early in childhood, there is a potential to develop complications later in life. All people with Transposition of the Great Arteries should have lifelong follow up with a congenital heart specialist. Our experts at the Irish Congenital Heart Centre are trained in congenital cardiology and have vast experience in treating people with Transposition of the Great Arteries. Find Out More >>

Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome is a complex and rare heart defect present at birth (congenital). The left side of the heart is critically underdeveloped in hypoplastic left heart syndrome. If your baby is born with hypoplastic left heart syndrome, the left side of the heart can't effectively pump blood to the body. Instead, the right side of the heart must pump blood to the lungs and to the rest of the body. Medication to prevent closure of the connection (ductus arteriosus) between the right and left sides, followed by either surgery or a heart transplant, is necessary to treat hypoplastic left heart syndrome. With advances in care, the outlook for babies born with hypoplastic left heart syndrome is better now than in the past. All people who are born with hypoplastic left heart syndrome will have undergone multiple complex cardiac surgeries and require lifelong follow up by a specialist congenital heart expert. Find Out More >>

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