Hypoplastic Left Heart Syndrome

What is Hypoplastic Left Heart Syndrome?

Also referred as HLHS, is a syndrome that is a very rare and complex heart defect that is congenital. With this syndrome, the heart’s left side is vastly undersized.

If the baby is born with this syndrome, the heart’s left side will not be able to pump blood efficiently to the body so the heart’s right side will need to do all the pumping of the blood to both lungs as well as the remainder of the body.

Drugs to stop closing of the link – ductus arteriosus – connecting the left and right side, followed by either heart transplant or repair surgery is necessary to treat this syndrome. With progress in healthcare, the viewpoint for those babies born with this syndrome is much improved than in the past.


Those babies born with this syndrome normally are severely ill immediately following birth. Symptoms of this syndrome include:

  • Skin color is grayish-blue
  • Difficult rapid breathing
  • Poor feeding
  • Cold feet and hands
  • Abnormally inactive or drowsy

For a baby with this syndrome, if the connections that are natural on the heart’s right and left side – ductus arteriosus and foramen ovale – are permitted to close up, the baby could slip into shock and die. Signs of shock include:

  • Clammy, cool skin that might be gray or pale
  • A weak and rapid pulse
  • Breathing that is abnormal and that may be either shallow and slow or quite rapid
  • Pupils dilated
  • Eyes that are dull and that only stare

A baby in shock might be either unconscious or conscious. If you believe the baby is in shock, call 911 immediately or the emergency number in your location.


This syndrome happens during growth of the fetus as the heart is developing. The reason is not known. But, if family has a child with this syndrome, the risk increases of having more with the identical syndrome.

A regular heart has 4 chambers, 2 on the left and 2 on the right. In executing the heart’s regular job – pumping of blood thru out the body – the heart’s right and left sides have diverse tasks. The right side circulates blood to the lungs where the blood is oxygen enriched and where it then circulates to the left side of heart. The heart’s left side circulates blood into a large blood artery called the aorta that moves the oxygen-rich blood to the remainder of the body.

With this syndrome, the heart’s left side can not correctly provide blood to the body since the left lower chamber or left ventricle is too undersized or in some cases does not even exist. Additionally, the valves on the heart’s left side – mitral and aortic valves – do not work correctly and the main vessel departing the heart – aorta – is less than normal.

For the first few days of life, the heart’s right side may pump blood to both the lungs and the rest of the body thru a normal opening – foramen ovale – between the heart’s upper chambers – atria – or thru a blood vessel connecting the pulmonary artery straight to the aorta or ductus arteriosus. When these 2 openings are connected and opened – ductus arteriosus and foramen ovale, they are known as being “patent”.

So, if the ductus arteriosus and foramen ovale close – which is what happens after the 1st day or 2 of life – the heart’s right side has no means to pump blood out to the body. But, numerous infants with this syndrome have an additional defect of the heart; a hole in the wall between the heart’s upper chambers – atrial septal defect – that lets the heart’s right side continue pumping blood to the remainder of the body even if the foramen ovale or ductus arteriosus closes.


Treatment for this syndrome involves a 3 step surgical process or a transplant with a new heart. If diagnosis is ready prior to the baby’s birth, physicians normally counsel that birth occurs at a hospital that has a cardiac surgery department.

Before Surgery

The baby’s doctor might advocate various alternatives to help administer this condition prior to transplant or surgery. They consist of:

Medication – Drugs like “alprostadil (Prostin VR)” widens the blood arteries and veins and keeps the “ductus arteriosus” open.

Breathing support – If the baby has problems with breathing, he/she might need support with a breathing apparatus or ventilator that makes certain sufficient oxygen delivery.


Intravenous fluids – the baby receives fluid thru an IV tube.

Atrial Septostomy – This process is to create a hole in-between the upper chambers of the heart especially if the “foramen ovale” closes. If the baby previously has an “atrial septal defect”, this process might not be needed.


Options surgically include a 3-step surgery intended to create blood flow that is normal in as well as out of the heart, letting the body obtain the oxygen-rich blood it requires.

Step 1: The Norwood operation

Surgery is normally carried out in the first few weeks of life. It entails rebuilding the aorta and directly connecting it to the heart’s right ventricle or lower chamber. This permits the right ventricle to efficiently pump blood to both the body and the lungs. After this surgery the skin of the baby will have a blue hue because the oxygen-poor and oxygen-rich blood continues to blend in the heart. Once the baby gets thru this stage of treatment the odds of survival increases.

Step 2: Hemi-Fontan and a bi-directional Glenn procedure

This process is normally executed between 4 and 12 months old. It decreases the job of the right ventricle by permitting it to push blood generally to the aorta and permitting most of the blood arriving from the body to flow straight to the lungs. Following this surgery, all blood that returns from the higher body is delivered to the lungs, so blood with extra oxygen is sent to the aorta to provide tissues and organs thru out the body.

Step 3: The Fontan process

This process is performed amid 18 months and 3 years. It lets the rest of the blood arriving from the body to go to the lungs. Following this process, there is no oxygen-poor and oxygen-rich blood blending in the heart and the baby’s skin no longer appears blue.

Another option for surgery is a heart transplant, particularly when the flaws are intricate. Babies with HLHS may be considered for a transplant. While waiting for a heart to be donated, the baby may need drugs until that heart becomes available.

Follow-up care

After a transplant or surgery, the child will require lifelong follow-up with a heart specialist or cardiologist who specializes in heart disease that is inherited, to manage the baby’s heart health. Several drugs might be needed to normalize the heart function. If the baby obtains a heart transplant, then anti-rejection drugs will be needed for the remainder of their life.

The child’s cardiologist might advise taking antibiotics prior to certain dental or other processes to avert infection particularly if the heart has not been repaired fully yet or if there are small flaws that remain after repair. In several cases, they will also advise that the child limit any physical activity.

Life expectancy

Although every incident is diverse, keep in mind that many children with this congenital heart syndrome grow up to lead productive and healthy lives.

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