Definition

What is hypoplastic left heart syndrome?

Hypoplastic left heart syndrome (HLHS) is a birth defect that affects normal blood flow through the heart. As the baby develops during pregnancy, the left side of the heart does not form correctly. Hypoplastic left heart syndrome is one type of congenital heart defect. Congenital means present at birth.

Hypoplastic left heart syndrome affects a number of structures on the left side of the heart that do not fully develop, for example:

  • The left ventricle is underdeveloped and too small.
  • The mitral valves is not formed or is very small.
  • The aortic valve is not formed or is very small.
  • The ascending portion of the aorta is underdeveloped or is too small.

Often, babies with hypoplastic left heart syndrome also have an atrial septal defect, which is a hole between the left and right upper chambers (atria) of the heart.

In a baby without a congenital heart defect, the right side of the heart pumps oxygen-poor blood from the heart to the lungs. The left side of the heart pumps oxygen-rich blood to the rest of the body. When a baby is growing in a mother’s womb during pregnancy, there are two small openings between the left and right sides of the heart: the patent ductus arteriosus and the patent foramen ovale. Normally, these openings will close a few days after birth.

In babies with hypoplastic left heart syndrome, the left side of the heart cannot pump oxygen-rich blood to the body properly. During the first few days of life for a baby with hypoplastic left heart syndrome, the oxygen-rich blood bypasses the poorly functioning left side of the heart through the patent ductus arteriosus and the patent foramen ovale. The right side of the heart then pumps blood to both the lungs and the rest of the body. However, among babies with hypoplastic left heart syndrome, when these openings close, it becomes hard for oxygen-rich blood to get to the rest of the body.

How common is hypoplastic left heart syndrome?

Hypoplastic left heart syndrome is rare. Please discuss with your doctor for further information.

Symptoms

What are the symptoms of hypoplastic left heart syndrome?

The common symptoms of hypoplastic left heart syndrome are:

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

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:

  • Cool, clammy skin that may be pale or gray
  • A weak and rapid pulse
  • Abnormal breathing that may be either slow and shallow or very rapid
  • Dilated pupils
  • Lackluster eyes that seem to stare

A baby who is in shock may be conscious or unconscious. If you suspect your baby is in shock, immediately call your local emergency number.

There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.

When should I see my 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:

  • Grayish-blue skin color
  • Rapid, difficult breathing
  • Poor feeding
  • Cold hands and feet
  • Being unusually drowsy or inactive

If your baby has any of the following signs of shock, call your local emergency number right away:

  • Cool, clammy skin that may be pale or gray
  • A weak and rapid pulse
  • Abnormal breathing that may be either slow and shallow or very rapid
  • Dilated pupils
  • Lackluster eyes that seem to stare

Causes

What causes hypoplastic left heart syndrome?

The causes of heart defects such as hypoplastic left heart syndrome among most babies are unknown. Some babies have heart defects because of changes in their genes or chromosomes. These types of heart defects also are thought to be caused by a combination of genes and other risk factors, such as things the mother comes in contact with in the environment or what the mother eats or drinks or the medicines the mother uses.

Risk factors

What increases my risk for hypoplastic left heart syndrome?

If you already have a child with hypoplastic left heart syndrome, you’re at a higher risk of having another baby with this condition or a similar condition.

Beyond family history, there are no clear risk factors for hypoplastic left heart syndrome.

Diagnosis & treatment

The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.

How is hypoplastic left heart syndrome diagnosed?

Hypoplastic left heart syndrome may be diagnosed during pregnancy or soon after the baby is born.

During Pregnancy

During pregnancy, there are screening tests (also called prenatal tests,) to check for birth defects and other conditions. Hypoplastic left heart syndrome may be diagnosed during pregnancy with an ultrasound, (which creates pictures of the body). Some findings from the ultrasound may make the health care provider suspect a baby may have hypoplastic left heart syndrome. If so, the health care provider can request a fetal echocardiogram, an ultrasound of the baby’s heart, to confirm the diagnosis.This test can show problems with the structure of the heart and how the heart is working with this defect.

After the Baby Is Born

Babies with hypoplastic left heart syndrome might not have trouble for the first few days of life while the patent ductus arteriosus and the patent foramen ovale (the normal openings in the heart) are open, but quickly develop signs after these openings are closed, including:

During a physical examination, a doctor can see these signs or might hear a heart murmur (an abnormal whooshing sound caused by blood not flowing properly). If a murmur is heard or other signs are present, the health care provider might request one or more tests to make a diagnosis, the most common being an echocardiogram. Echocardiography also is useful for helping the health care provider follow the child’s health over time.

How is hypoplastic left heart syndrome treated?

Treatments for some health problems associated with hypoplastic left heart syndrome might include:

Medicines

Some babies and children will need medicines to help strengthen the heart muscle, lower their blood pressure, and help the body get rid of extra fluid.

Nutrition

Some babies with hypoplastic left heart syndrome become tired while feeding and do not eat enough to gain weight. To make sure babies have a healthy weight gain, a special high-calorie formula might be prescribed. Some babies become extremely tired while feeding and might need to be fed through a feeding tube.

Surgery

Soon after a baby with hypoplastic left heart syndrome is born, multiple surgeries done in a particular order are needed to increase blood flow to the body and bypass the poorly functioning left side of the heart. The right ventricle becomes the main pumping chamber to the body. These surgeries do not cure hypoplastic left heart syndrome, but help restore heart function. Sometimes medicines are given to help treat symptoms of the defect before or after surgery. Surgery for hypoplastic left heart syndrome usually is done in three separate stages:

Norwood Procedure

This surgery usually is done within the first 2 weeks of a baby’s life. Surgeons create a “new” aorta and connect it to the right ventricle. They also place a tube from either the aorta or the right ventricle to the vessels supplying the lungs (pulmonary arteries). Thus, the right ventricle can pump blood to both the lungs and the rest of the body. This can be a very challenging surgery. After this procedure, an infant’s skin still might look bluish because oxygen-rich and oxygen-poor blood still mix in the heart.

Bi-directional Glenn Shunt Procedure

This usually is performed when an infant is 4 to 6 months of age. This procedure creates a direct connection between the pulmonary artery and the vessel (the superior vena cava) returning oxygen-poor blood from the upper part of the body to the heart. This reduces the work the right ventricle has to do by allowing blood returning from the body to flow directly to the lungs.

Fontan Procedure

This procedure usually is done sometime during the period when an infant is 18 months to 3 years of age. Doctors connect the pulmonary artery and the vessel (the inferior vena cava) returning oxygen-poor blood from the lower part of the body to the heart, allowing 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 no longer mix in the heart and an infant’s skin will no longer look bluish.

Infants who have these surgeries are not cured; they may have lifelong complications.

Infants with hypoplastic left heart syndrome will need regular follow-up visits with a cardiologist (a heart doctor) to monitor their progress. If the hypoplastic left heart syndrome defect is very complex, or the heart becomes weak after the surgeries, a heart transplant may be needed. Infants who receive a heart transplant will need to take medicines for the rest of their lives to prevent their body from rejecting the new heart.

Lifestyle changes & home remedies

What are some lifestyle changes or home remedies that can help me manage hypoplastic left heart syndrome?

The following lifestyles and home remedies might help you cope with hypoplastic left heart syndrome:

  • Seek support. Ask for help from family members and friends. Talk with your child’s cardiologist about support groups and other types of assistance that are available near you.
  • Record your baby’s health history. It will be important to write down your baby’s diagnosis, medications, surgery and other procedures and the dates they were performed, as well as the name and phone number of your child’s cardiologist, emergency contact numbers for your child’s doctors and hospital, and any other important information about your baby’s care. It’s also important to include a copy of the operative report from your child’s surgeon in your records. This information will help you recall the care your child has received, and it will be useful for doctors who are unfamiliar with your baby to review his or her complex health history.
  • Talk about your concerns. As your child grows, you may worry about activities in which he or she can safely participate. Talk with the cardiologist about which activities are best for your child. If some are off-limits, encourage your child in other pursuits rather than focusing on what he or she can’t do. If other issues about your child’s health concern you, discuss them with your child’s cardiologist, too.

If you have any questions, please consult with your doctor to better understand the best solution for you.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Sources

Review Date: November 16, 2017 | Last Modified: November 16, 2017

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