Filed under: Heart & Vascular
Hypoplastic left heart syndrome is a complex and rare heart defect present at birth (congenital). In hypoplastic left heart syndrome, the left side of the heart is critically underdeveloped.
If your baby is born with hypoplastic left heart syndrome, the left side of the heart can't effectively pump blood to the body, so the right side of the heart must pump blood both 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.
Babies born with hypoplastic left heart syndrome usually are seriously ill immediately after birth. Hypoplastic left heart syndrome symptoms include:
In a baby with hypoplastic left heart syndrome, if the natural connections between the heart's left and right sides (foramen ovale and ductus arteriosus) are allowed to close, he or she may go into shock and may die. Signs of shock include:
A baby who is in shock may be conscious or unconscious. If you suspect your baby is in shock, immediately call 911 or your local emergency number.
When to see a doctor
It's more likely that your baby would be diagnosed with hypoplastic left heart syndrome either before birth or soon after. However, you should seek medical help if you notice that your baby has the following symptoms:
If your baby has any of the following signs of shock, call 911 or your local emergency number right away:
Hypoplastic left heart syndrome occurs during fetal growth when the baby's heart is developing. The cause is unknown. However, if your family has one child with hypoplastic left heart syndrome, the risk of having another with the same condition is increased.
A normal heart has four chambers, two on the right and two on the left. In performing its basic job — pumping blood throughout the body — the heart uses its left and right sides for different tasks. The right side moves blood to the lungs. In the lungs, oxygen enriches the blood, which then circulates to the heart's left side. The left side of the heart pumps blood into a large vessel called the aorta, which circulates the oxygen-rich blood to the rest of the body.
What happens in hypoplastic left heart syndrome
In hypoplastic left heart syndrome, the left side of the heart can't properly supply blood to the body because the lower left chamber (left ventricle) is too small or in some cases it may not even exist. In addition, the valves on the left side of the heart (aortic valve and mitral valve) don't work properly, and the main artery leaving the heart (aorta) is smaller than normal.
For the first several days of life, the right side of the heart can pump blood both to the lungs and to the rest of the body through a natural opening (foramen ovale) between the upper chambers of the heart (atria) or through a blood vessel that connects the pulmonary artery directly to the aorta (ductus arteriosus). When the foramen ovale and the ductus arteriosus are open, they are referred to as being "patent."
If the ductus arteriosus and the foramen ovale close — which they normally do after the first day or two of life — the right side of the heart has no way to pump blood out to the body. However, many infants with hypoplastic left heart syndrome also have another heart defect, a hole in the wall between the upper chambers of the heart (atrial septal defect), that allows the right side of the heart to continue pumping blood to the body even if the ductus arteriosus or foramen ovale closes.
If you already have a child with hypoplastic left heart syndrome, you're at a higher risk of having another baby with this condition.
Beyond family history, there are no clear risk factors for hypoplastic left heart syndrome.
Without surgery, hypoplastic left heart syndrome is fatal, usually within the first week or two of life.
With treatment, many babies survive, although most will have complications later in life. Some of the complications include:
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 your baby is born, his or her doctor may suspect a heart defect, such as hypoplastic left heart syndrome, if your baby has grayish-blue skin or has trouble breathing. Your baby's doctor may also suspect a heart defect if he or she hears a heart murmur — an abnormal whooshing sound caused by turbulent blood flow.
Doctors typically 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. In a baby with hypoplastic left heart syndrome, the echocardiogram reveals a smaller than normal left ventricle and aorta. Because this test can track blood flow, it also shows blood moving from the right ventricle into the aorta. In addition, an echocardiogram can identify associated heart defects, such as an atrial septal defect.
Treatment for hypoplastic left heart syndrome involves either a three-step surgical procedure or a heart transplant. If the diagnosis has been made before the baby is born, doctors usually recommend delivery at a hospital with a cardiac surgery center.
Your baby's doctor may recommend several options to help manage the condition before surgery or transplant. They include:
Surgical options include a three-step surgical procedure designed to create normal blood flow in and out of the heart, allowing the body to receive the oxygen-rich blood it needs.
Another surgical option is a heart transplant, especially when the defects are complex. Babies with hypoplastic left heart syndrome can be considered for a transplant. While awaiting a heart transplant, your baby may require medications until a donor heart becomes available.
After surgery or a transplant, your baby will need lifelong follow-up care with a heart doctor (cardiologist) who specializes in congenital heart disease, to monitor his or her heart health. Some medication may be necessary to regulate heart function. If your baby receives a heart transplant, anti-rejection medication will be necessary for the rest of his or her life to combat rejection of the new heart.
Your child's cardiologist may recommend taking antibiotics before certain dental or other procedures to prevent infections, especially if the heart hasn't been fully repaired yet or if there are small defects that remain after repair. In some cases, he or she may also recommend that your child limit physical activity.
There's no known way to prevent hypoplastic left heart syndrome. If you have a family history of heart defects, or if you already have a child with a congenital heart defect, before getting pregnant consider talking with a genetic counselor and a cardiologist experienced in congenital heart defects.
Caring for a baby with a serious heart problem, such as hypoplastic left heart syndrome, can be challenging. Here are some strategies that may help make it easier:
Although every circumstance is different, remember that many children with congenital heart defects grow up to lead healthy lives.