About congenital heart disease

Congenital heart disease is a general term 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
  • acyanotic heart disease

Cyanotic heart disease

Cyanotic heart is where problems with the heart mean there isn't enough oxygen present in the blood.

Babies born with cyanotic heart disease generally have a blue-coloured tinge to areas such as their fingers, toes and lips because of a lack of oxygen. 

They may also experience symptoms of:

  • breathlessness
  • chest pain
  • palpitations
  • fainting
  • fatigue

Acyanotic heart disease

Acyanotic heart disease is where the blood contains enough oxygen but it's pumped abnormally around the body.

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

In this group of conditions there can be a significant increase in blood pressure, putting the heart under more strain as it works much harder. This can weaken the heart, and increases the risk of developing heart failure, where the muscle is unable to efficiently pump blood around the body.

In addition, the blood pressure in the lungs is often too high. This is known as pulmonary hypertension and can damage the lungs and cause symptoms such as:

  • breathlessness
  • fatigue
  • dizziness
  • fainting

How common is congenital heart disease?

Congenital heart disease is the most common type of birth defect, with 1 in 180 babies being born with the condition.

Some babies born with congenital heart disease will require immediate surgery after birth, while many others will probably require surgery or medication at some point during their childhood.  

Congenital heart disease can sometimes develop alongside 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.

Outlook for congenital heart disease

The outlook for congenital heart disease varies depending on the type and severity of the heart defect.   

Research into the causes and improved treatments have meant that, 80% of children with congenital heart disease will survive 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) or Adult Congenital Heart Disease (ACHD).

Symptoms of congenital heart disease

As stated in the introduction, the two main types of congenital heart disease are:

  • cyanotic heart disease
  • acyanotic heart disease

Symptoms of cyanotic heart disease

The symptoms of cyanotic heart disease include:

  • a blue coloured tinge to the lips, fingers and toes (cyanosis)
  • palpitations
  • fainting
  • fatigue
  • chest pains
  • breathing problems

Children with cyanotic heart disease have lower levels of oxygen in their blood, this is known as hypoxia.

Sometimes, their oxygen levels can fall further and cause additional symptoms such as anxiety and confusion or disorientation.

Symptoms of acyanotic heart disease

The symptoms of acyanotic heart disease include:

  • severe tiredness
  • palpitations
  • chest pain
  • 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
  • delayed growth

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

Causes of congenital heart disease

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

Find out how your heart works, on the British Heart Foundation website.

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

As outlined in the introduction, the two main types of congenital heart disease are:

  • cyanotic heart disease
  • acyanotic heart disease

Find common causes of each below.

Common types of acyanotic heart disease

Ventricular septal defect (VSD)

Ventricular septal defect (VSD) is a very 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 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 and pressure of the 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 atria rather than the ventricles.

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.

Find out more about ASD on the British Heart Foundation website.

Pulmonary stenosis

In pulmonary stenosis, the pulmonary valve in the right side of the heart 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.

Find out more about pulmonary stenosis on the British Heart Foundation website.

Aortic stenosis

In aortic stenosis, the aortic valve in the left side of the heart 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.

Find out more about aortic stenosis on the British Heart Foundation website.

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 through the placenta.

Therefore, the ductus ateriosus acts as a bypass, 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 and back 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 aorta sits over both the left and right ventricles, instead of just the left ventricle in a normal heart (overriding 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 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.

Find out more about TOF on the British Heart Foundation website.

Transposition of the great arteries (TGA)

Transposition of the great arteries (TGA) is a major cause of cyanotic heart disease.

In cases of TGA, the pulmonary artery is attached to the left side of the heart, and the aorta is attached to the right side of the heart. This leads to oxygen-low blood, which should be pumped into the lungs, being pumped around the body, causing symptoms of cyanotic heart disease.

Find out more about TGA on the British Heart Foundation website.

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 the viral infection rubella (also known as German measles) 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 exceed the recommended daily alcohol intake during pregnancy have an increased risk of their baby being born with congenital heart disease. 

Alcohol is best avoided during pregnancy; however no more than 2-3 units should be consumed on a daily basis for any adult.

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
  • Noonan syndrome

Diagnosing congenital heart disease

An increasing number of cases of congenital heart disease are now diagnosed by carrying out a foetal echocardiograph before a baby is born.

A foetal echocardiograph is made possible by using a type of ultrasound scanner that has been specially designed to build a picture of the unborn baby’s heart. It should be carried out during routine antenatal examinations, usually sometime between the 18th and 20th week of pregnancy.

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. 

Possible signs that your child may have a cyanotic heart disease include:

  • problems feeding
  • slow growth
  • shortness of breath after exercising
  • tiredness after exercising
  • 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 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.

Find out more about an echocardiogram on the British Heart Foundation website.

Electrocardiogram (ECG)

An electrocardiogram (ECG) is a test that measures the electrical activity of the child’s heart. Electrodes are placed on the skin across the chest, arms and legs, and then connected to an ECG machine. The machine analyses the electrical signals produced by the heart in order to assess the heart rhythm.

Find out more about an ECG on the British Heart Foundation website.

Chest X-ray

A chest X-ray of the heart and lungs can check whether there are any abnormalities in the lungs, or whether the heart is larger than normal. Both of these can be signs of congenital heart disease.

Find out more about a chest x-ray on the British Heart Foundation website.

Pulse oximetry

Pulse oximetry is a test that measures how much oxygen is present in the 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, and gives a percentage reading. 

A healthy person should have a reading of 94% or above. It is common for those with cyanotic heart defects to have readings below this value.

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 to help guide it.

A contrast dye that shows up on X-rays can 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. Blood pressure readings in different parts of the heart can also be taken; this will help with diagnosis and treatment planning.

Cardiac catheterisation is usually performed under a local anaesthetic and is a relatively painless procedure.

Treating congenital heart disease

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


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's minimally invasive, which means that your child will not have to have open heart surgery.

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 may be stopped and a machine used to pump blood around your child’s body (bypass machine). 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 more serious cases of congenital heart disease, the heart may be too damaged, and the child too ill, for corrective 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 assist in pumping blood 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 in a very unstable condition, they will be prioritised whereas more stable children will have to wait for a longer period of time.

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.

Find out more about heart transplantation on the British Heart Foundation website.

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 may be required. This involves a patch being stitched directly over the defect.


If your child is diagnosed with a stenosis (a narrowing one of their valves) the treatment that is recommended will depend on the extent of the stenosis and if they are symptomatic.

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 more serious cases of stenosis, it's sometimes necessary to replace the valve using 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.

For people who are too ill or weak to withstand the effects of open heart surgery, a catheter approach can be used. The catheter is passed through a blood vessel in the groin and up into the heart. A replacement valve is passed through the catheter and into position.

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 a special type of 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 (TOF) who are experiencing severe symptoms of breathlessness may require emergency surgery such 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 affected arteries are cut and reattached to their correct position on the other side of the heart.

Congenital heart disease in adulthood

About 80% of children with congenital heart disease will 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 closely supervised 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's 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 on-going support and advice.

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

Complications of congenital heart disease

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.


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
  • shortness of breath

Endocarditis will need to be with injections of antibiotics (intravenous antibiotics). This will involve a hospital stay for several weeks.

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.

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

Last updated:
18 November 2022