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Congenital heart disease

Page last reviewed: 13/07/2011

Congenital heart disease is a general term that is used to refer to a series of birth defects that affect the heart.

Types of congenital heart disease

There are over 30 different types of heart defect. The two main types of congenital heart disease are cyanotic heart disease and acyanotic heart disease.

  • Cyanotic heart disease: where problems with the heart mean that there is not enough oxygen present in the blood.
  • Acyanotic heart disease: where the blood contains enough oxygen but it is pumped abnormally around the body.

Cyanotic heart disease

Babies born with cyanotic heart disease usually have blue-coloured fingers, toes and lips as a result of a lack of oxygen. They will also experience symptoms of:

  • breathlessness,
  • fainting, and
  • fatigue.

Acyanotic heart disease

Babies born with acyanotic heart disease may not have any apparent symptoms but, over time, the condition can cause problems.

As the pressure of the blood is often abnormally high, the heart has to work harder to pump the blood. This can weaken the heart, and increases the risk of it failing.

Also, the blood pressure in the lungs is often too high, which is known as pulmonary hypertension. High blood pressure can damage the lungs and cause symptoms such as:

  • breathlessness,
  • fatigue,
  • dizziness, and
  • fainting.

How common is congenital heart disease?

Congenital heart disease is the most common type of birth defect, with six out of every 1,000 babies being born with the condition.

Half of all babies born with congenital heart disease will require immediate surgery after birth, while the other 50% will probably require surgery or medication at some point during their childhood.

Congenital heart disease can sometimes develop as the result of certain genetic conditions, such as Down's syndrome. An infection during pregnancy, such as rubella, can also cause congenital heart disease.

However, many cases of congenital heart disease have no clear cause.


The outlook for congenital heart disease varies depending on the type and severity of the heart defect. However, in most cases, the outlook is reasonably good.

Due to advances in heart surgery, 85% of children with congenital heart disease will survive into adulthood.

Many people with congenital heart disease are now living well into adulthood. This poses new challenges for healthcare services because some of these adults have complex health needs and require life-long specialised care.

In response to this, the Department of Health has recommended the creation of specialised centres to care for adults with congenital heart disease. Congenital heart disease in adults is sometimes known as 'grown-up congenital heart disease' (GUCH).

Ultrasound scans

Ultrasound scans are a way of producing pictures of inside the body using soundwaves.

Heart valves

Heart valves are four sets of flaps that control the direction that blood pumps around the heart.


Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.


Arteries are blood vessels that carry blood from the heart to the rest of the body.


Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen.

Page last reviewed: 13/07/2011

Cyanotic heart disease

The symptoms of cyanotic heart disease include:

  • a bluish discolouring of the lips, fingers and toes (cyanosis), 
  • fainting,
  • chest pains, and
  • breathing problems. Children will often adopt a squatting posture which can help to relieve the symptoms of breathlessness.

Children with cyanotic heart disease often experience episodes of hypoxia. Hypoxia occurs when the body is suddenly starved of oxygen.

During an episode of hypoxia, a child may become anxious, start hyperventilating, and their skin will have a blue tinge to it (cyanosis).

Acyanotic heart disease

The symptoms of acyanotic heart disease include:

  • severe tiredness,
  • chest pain, and
  • shortness of breath (particularly during activities such as climbing the stairs).

Common symptoms of congenital heart disease

There are some symptoms that are present in both cyanotic and acyanotic heart disease. These include:

  • poor appetite and feeding difficulties,
  • sweating, particularly when a baby is feeding, and
  • delayed growth.

Children with acyanotic heart disease are usually underweight, and children with cyanotic heart disease are usually underweight and small for their age. 

Page last reviewed: 13/07/2011

How the heart works

To understand how congenital heart disease can affect your child's heart and general health, it is useful to understand how a healthy heart works.

The heart is essentially a pump that is made up of four chambers:

  • the left atrium,
  • the left ventricle,
  • the right atrium, and
  • the right ventricle.

There are also four valves that control how the blood flows through the heart and around the body. These valves are:

  • the mitral valve,
  • the aortic valve,
  • the tricuspid valve, and
  • the pulmonary valve.

The heart's purpose is to supply oxygen-rich blood to the body's cells and tissues. Blood is pumped into the lungs where it picks up oxygen.

The oxygen-rich blood is transported to the body's cells and tissues, which remove the oxygen from the blood. The oxygen-low blood then flows back to the heart and is pumped into the lungs to obtain more oxygen for the body.

Congenital heart disease develops when abnormalities in the heart's structure prevent it from working as it should.

Common types of acyanotic heart disease

Ventricular septal defect (VSD)

Ventricular septal defect (VSD) is the most common cause of acyanotic heart disease. In cases of VSD, there is a hole between the left and right ventricle.

As blood pressure is higher on the left-hand side of the heart, blood is pushed out of the left ventricle through the hole and into the right ventricle.

The heart then has to work harder to pump the excess blood out of the right ventricle, which can put a strain on the heart. The excess level of blood can also increase the blood pressure in the lungs and damage them (pulmonary hypertension).

Atrial septal defect (ASD)

Atrial septal defect (ASD) is a similar type of defect to VSD, but the hole is between the left and right atriums rather than the ventricle. ASD can place extra strain on the heart, and potentially damage the lungs.

When referring to a 'hole in the heart', healthcare professionals are usually referring to either VSD or ASD.

Pulmonary stenosis

In pulmonary stenosis, the pulmonary valve is unusually narrow meaning that the heart has to work harder to pump blood into the lungs, which can put a strain on the heart.

Aortic stenosis

In aortic stenosis, the aortic valve is unusually narrow, which means that the heart has to work harder to pump blood through the valve.

Because the aortic valve is the main route for oxygen-rich blood to supply the body, the narrowing can lower the body's oxygen supply, which can cause symptoms of breathlessness and dizziness.

Patent ductus ateriosus (PDA)

Patent ductus ateriosus (PDA) is a duct or passage in the heart that is meant to close shortly after birth.

When an unborn baby is in the womb, there is no need for the baby's heart to send blood to the lungs because the baby is getting all the oxygen it needs from the mother.

Therefore, the ductus ateriosus acts as a bypass between the aortic and pulmonary valve, meaning that the blood can flow back into the heart without entering the lungs.

Shortly after birth, the duct should close as the baby begins to breathe normally. However, in cases of PDA, the duct fails to completely close, which means that some oxygen-rich blood that is meant to be pumped away from the lungs leaks back through the duct, into the pulmonary valve, and into the lungs.

This can place strain on the heart and the lungs because they have to work harder to compensate for the problems caused by the duct.

Common types of cyanotic heart disease

Tetralogy of Fallot (TOF)

Tetralogy of Fallot (TOF) is the most common cause of cyanotic heart disease. TOF is not one heart defect but a combination of four different heart defects. Tetralogy is a Greek word that means 'four-fold', and Fallot is the name of the doctor who first identified the condition.

In cases of TOF, there are four defects that affect the heart:

  • A hole between the left and right ventricle (Ventricular Septal Defect).
  • A narrowing of the pulmonary valve (pulmonary stenosis).
  • The muscles of the right ventricle are unusually thick (right ventricular hypertrophy).
  • The aortic valve is in the wrong position (displaced aorta).

As a result of this complex set of heart defects, oxygen-rich blood and oxygen-low blood become mixed. This leads to blood with a lower-than-normal oxygen content being pumped around the body.

As the body's cells and tissue are not receiving enough oxygen, the child will develop symptoms of cyanotic heart disease, such as blue skin and breathlessness.

Transposition of the great arteries (TGA)

Transposition of the great arteries (TGA) is the second most common cause of cyanotic heart disease.

In cases of TGA, the pulmonary and aortic valves, and the arteries that they are connected to, literally swap positions. This leads to oxygen-low blood, which should be pumped into the lungs, being pumped around the body, causing symptoms of cyanotic heart disease.

Risk factors for congenital heart disease

In many cases of congenital heart disease, there is no clear reason why a baby is born with a defective heart. The known risk factors for congenital heart disease are listed below.

Maternal diabetes

Women with diabetes are five times more likely to give birth to a baby with congenital heart disease compared with women who do not have diabetes. It is estimated that out of every 100 pregnancies in women with diabetes, three to four will result in the birth of a baby with a heart defect.

The increased risk is thought to be due to the high levels of insulin in the blood, which may interfere with the development of the foetus.


The viral infection rubella (also known as German measles) is a major risk factor for congenital heart disease if a woman contracts an infection during early pregnancy.

If a woman contracts rubella during the first 12 weeks of pregnancy, there is an 80% chance that her baby will be born with a birth defect, such as congenital heart disease.

Maternal alcohol abuse

Mothers who drink too much alcohol during pregnancy have an increased risk of their baby being born with congenital heart disease. It is estimated that 30-50% of babies born to mothers who are heavy drinkers (two or three units or more of alcohol a day) will have congenital heart disease.

Genetic conditions

There are a number of genetic conditions (health conditions that a baby inherits from one or both parents) that can cause congenital heart disease.

Down's syndrome is the most widely known genetic condition that can cause congenital heart disease. Down's syndrome is a condition where children are born with a range of disabilities as the result of a genetic abnormality. Approximately half of children with Down's syndrome will have congenital heart disease.

Other genetic conditions linked to congenital heart disease include:

  • Turner syndrome, and
  • Noonan syndrome.

Page last reviewed: 13/07/2011

Antenatal diagnosis

An increasing number of cases of congenital heart disease are now diagnosed before a baby is born. This can be done by carrying out a foetal echocardiography.

A foetal echocardiography is a type of ultrasound scanner that has been specially designed to build a picture of the insides of the chambers of the heart.

Foetal echocardiography should be carried out during routine antenatal examinations, usually some time between the 18th and 20th week of pregnancy.

However, it is not always possible to detect heart defects (particularly mild ones) using a foetal echocardiography.

Postnatal diagnosis

If a baby is born with cyanotic heart disease, a diagnosis can usually be made quickly and confidently due to the distinctive blue colour of their skin.

If your baby is born with acyanotic heart disease, their symptoms may not become immediately apparent for several months, or possibly years, after birth. In some types of acyanotic heart disease, symptoms are not apparent until a child reaches three years of age.

Possible signs that your child may have acyanotic heart disease include:

  • problems feeding,
  • slow growth,
  • shortness of breath after exercising,
  • tiredness after exercising, and
  • swelling of their hands, feet and ankles.

You should contact your GP if your child has any of the above symptoms. Further testing can confirm or disprove a diagnosis of congenital heart disease.

Further testing


An echocardiogram may be used to check the inside of your child's heart. Sometimes, underlying problems with the heart, which were missed during a foetal echocardiogram, can be detected as a child grows up.


An electrocardiogram is a test that measures the electrical activity of the child's heart. Electrodes are placed on the skin around the heart, and then connected to a computer. The computer analyses the electrical signals produced by the heart in order to assess how well the heart is beating.

Chest X-ray

A chest X-ray of the heart and lungs can check whether there is an excess amount of blood in the lungs, or whether the heart is larger than normal. Both of these can be signs of heart disease.

Pulse oximetry

Pulse oximetry is a test that measures how much oxygen is present in your child's blood. The test involves placing a special sensor on your child's fingertip, ear or toe. The sensor sends out light waves. A computer that is connected to the sensor measures how the light waves are being absorbed.

Oxygen can affect how the light waves are being absorbed, so by analysing the results, the computer can quickly determine how much oxygen is present in your child's blood.

Cardiac catheterisation

Cardiac catheterisation is a useful way of finding out more information about exactly how the blood is pumping through the child's heart.

During a cardiac catheterisation, a small flexible tube, known as a catheter, will be inserted into one of the child's blood vessels, usually in the groin or arm. The tube is moved up into the heart, using X-rays or MRI scanners to help guide it.

The end of the tube contains a tiny blood pressure monitor, which can be used to take blood pressure readings in different parts of the heart.

A coloured dye that shows up on X-rays can also be injected into the tube. The dye can then be studied as it moves through the heart, enabling medical staff to see how well each chamber of the heart is working.

Cardiac catheterisation is performed under a local anaesthetic and is therefore painless.

Page last reviewed: 13/07/2011

There are a number of different surgical techniques that can be used to treat congenital heart disease.


A catheter, similar to the tube that is used during diagnosis, is inserted into the heart, and tools are passed down the catheter to repair the heart defects.

The advantage of this type of surgery is that it is non-invasive, which means that your child will not have to have a major surgical incision (cut) made in their chest.

Open heart surgery

For more serious types of heart defects, it may be necessary to operate directly on the heart. During open heart surgery, the heart will be stopped and a machine used to pump blood around your child's body.

An incision is made in your child's chest so that the heart defects can be surgically repaired, or damaged parts of the heart, such as the valves, can be replaced.

Heart transplant

In the most serious cases of congenital heart disease, it may be necessary to remove the damaged heart and replace it with a healthy heart that has been donated by the family of a child who has recently died.

Treatment for common types of congenital heart disease

Specific treatments for the most common types of congenital heart disease are described below.

Septal defects

If your child is diagnosed with a ventricular septal defect (VSD) or an atrial septal defect (ASD), the recommended treatment will depend on the size of the defect.

If the defect is small, a policy of 'watchful waiting' may be recommended, where your child receives no immediate treatment but their health is carefully monitored. This is because 90% of small defects will close as the child grows older.

In cases of mild to medium-sized defects, it may be possible to seal the defect using a catheter. The catheter is guided to the site of the hole, and a specially designed mesh is passed through the catheter to seal the defect.

In cases of medium to large-sized defects, open heart surgery will probably be required. This involves a patch being stitched directly over the defect.


If your child is diagnosed with stenosis (narrowing of their aorta or pulmonary valve) the treatment that is recommended will depend on the extent of the stenosis.

In mild cases, a policy of 'watchful waiting' may be recommended. Medication that lowers blood pressure may also be recommended to reduce the strain on your child's heart and lungs.

In more serious cases of stenosis, a catheter can be used to widen the valve. A small balloon is passed up through the catheter and then inflated to widen the affected valve. This is known as a balloon angioplasty. Once the valve has been widened, the balloon is removed. Sometimes, a metal coil (stent) is used to keep the valve widened.

In the most serious cases of stenosis, it is sometimes necessary to replace the valve during open heart surgery.

Replacement valves can be obtained from human donors, or made from artificial materials, such as titanium, or taken from pigs and modified for human use. Pigs are used because their hearts are the most similar to the human heart.

An alternative technique, which involves using a catheter to replace the aortic valve, has recently become available. The technique is known as catheter insertion of a new aortic valve.

The catheter is passed through the groin and up into the heart, and then a replacement valve is moved through the catheter and into position.

As yet, there is not enough available evidence on the long-term safety or effectiveness of catheter insertion. Therefore, this type of treatment is usually only recommended for people who are too ill or weak to withstand the effects of open heart surgery.

Patent ductus ateriosus (PDA)

Many cases of patent ductus ateriosus (PDA) can be treated shortly after birth, using medication.

Two types of medication - indomethacin and ibuprofen - have been shown to effectively stimulate the closure of the duct that is responsible for PDA.

If a PDA does not respond to medication, a catheter can be used to seal the duct with a metal coil or plug.

Tetralogy of Fallot (TOF)

Babies born with Tetralogy of Fallot (FOT) who are experiencing severe symptoms of breathlessness may require emergency surgery to restore normal lung function. This can be done using a procedure known as a Blalock-Taussig shunt (a BT shunt).

During a BT shunt, an artery is diverted (or shunted) into the lungs so that a supply of oxygen-rich blood becomes available.

Further open heart surgery is then recommended when the baby is old enough to withstand the after-effects of surgery. During open heart surgery, the defect between the ventricles is sealed and the pulmonary valve is widened.

Transposition of the great arteries (TGA)

Transposition of the great arteries (TGA) will require open heart surgery, which is usually done shortly after your baby is born.

A surgical technique, known as an arterial switch, is usually used to treat cases of TGA. During an arterial switch, the arteries that are connected to the pulmonary and aortic valves are cut and reattached to their correct position on the other side of the heart.

Heart transplant

In the most serious cases of congenital heart disease, the heart may be too damaged, and the child too ill, for surgery to be safely carried out. In this circumstance, their heart may have to be replaced with a donated heart.

If your child requires a heart transplant, their details will be placed on the National Transplant Database (NTD).

Depending on the condition of your child's heart, it may be necessary to keep them in hospital in order to support the function of their heart until a donated heart becomes available. Machines, such as the ventricle assist device (VAD), act like an external mechanical heart, and can pump oxygen around the body.

Priority for heart transplants is based on clinical need, rather than on a first-come-first-served basis. If your child is very ill, a donated heart may be found within a few weeks. However, if your child is less ill, they may have to wait several months for a heart to become available.

Once a donated heart of the right size and blood group becomes available, you will be contacted by the transplant team and asked to go to the transplant unit as soon as possible. You may be given a bleeper so that you can be contacted as soon as possible.

Congenital heart disease in adulthood

About 85% of children with congenital heart disease will respond well to treatment and survive into adulthood. Living as an adult with congenital heart disease involves a new set of challenges.

Some adults will require specialised care. Routine medical procedures, such as giving birth or having a general anaesthetic, will need to be carried out by specialist staff with experience in treating adults with congenital heart disease.

There is also the risk that previous heart surgery, such as the insertion of a replacement valve, will fail and that further surgery will be required.

Due to these factors, it is recommended that older teenagers register with a specialised adult congenital heart disease clinic. The clinic will be able to provide regular check-ups and assessments, liaise with other specialised medical services as required, and provide ongoing support and advice.

Your GP or treatment team can give you more information about services in your area for adults with congenital heart disease.

See Useful links for more information about living with congenital heart disease.

Page last reviewed: 13/07/2011

Developmental delays

Many children with congenital heart disease will experience delays in their development, and may take longer to reach certain stages in their development, such as walking or talking.

Some children with congenital heart disease also have associated learning difficulties and require specialised educational and psychological assistance.

If your child has congenital heart disease, your local educational authority should draw up an individual education plan (IEP). The IEP makes an assessment of your child's current and future needs, and provides access to any specialised services that your child needs, such as speech and language therapy or an educational psychologist.

The IEP will take into account what level of physical activity is safe for your child. Children with congenital heart disease should be encouraged to be as active as possible, but certain activities, such as contact sports, may have to be avoided.

See Useful links for more information about the non-medical needs of children with congenital heart disease, and the support that is available to meet those needs.


Both children and adults with congenital heart disease have an increased risk of developing endocarditis. Endocarditis is an infection of the lining of the heart and, left untreated, it can be life-threatening because it damages the valves of the heart.

Symptoms of endocarditis include:

  • fever,
  • chills,
  • sweating (including night sweats),
  • muscular aches and pains,
  • chest pain,
  • coughs,
  • weakness and fatigue,
  • headache, and
  • shortness of breath.

Endocarditis will need to be treated in hospital with injections of antibiotics (intravenous antibiotics).

Endocarditis usually develops when an infection in another part of the body, such as on the skin or the gums spreads through the blood into the heart.

Due to the risk of gum disease leading to endocarditis, it is very important that you have excellent oral hygiene if you have congenital heart disease. See Useful links for information about gum disease and how to prevent it.

It is also usually recommended that you avoid having any cosmetic procedure that involves the piercing of the skin, such tattoos or body piercings.

See Useful links for more information about endocarditis. 

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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