Congenital heart defects

by | Babies and Pregnancy, Heart Attacks and Strokes

Congenital heart defects are problems with the structure of the heart that are present from birth. Congenital (which means ‘from birth’) heart defects develop in the first few weeks of pregnancy. In Australia, as many as one baby in 100 is born with a heart defect.

Congenital heart defects (sometimes called congenital heart disease) can affect the walls of the heart, valves within the heart or the blood vessels entering or leaving the heart. Sometimes several defects are present. Many simple congenital heart defects produce no symptoms and do not need treatment.

These days, even complex congenital heart defects can usually be repaired in infancy or childhood, but ongoing care throughout life is still needed. It’s likely that there are now more adults than children living with congenital heart disease in Australia.

Symptoms of congenital heart defects

Symptoms will depend on your age, the type of heart defect you have, and how much it affects blood flow and your heart’s ability to pump blood. Many people with congenital heart defects have no symptoms at all. In some of these people, the defect may only be discovered when your doctor notices a heart murmur during a routine examination. Some heart defects can be detected before your baby is born during routine pregnancy ultrasounds.

Complex and life-threatening congenital heart defects are usually detected soon after birth. Symptoms in babies include:

  • difficulty feeding or becoming sweaty or breathless when feeding;
  • being slow to put on weight;
  • having a blue tinge to the skin, lips and fingernails – called cyanosis – that may come and go; and
  • fast breathing.

Simple heart defects may not cause symptoms or may not be detected until children are older. Symptoms in older children can include:

  • easily becoming breathless or tired during activities;
  • difficulty keeping up with their friends while playing;
  • fainting during or after exercise;
  • poor growth; and
  • frequent chest infections.

Some people may not have symptoms until adulthood, while others may have symptoms that reappear after many years. Symptoms in adults can include:

  • breathlessness;
  • tiredness;
  • cyanosis; and
  • abnormal heart rhythms (arrhythmias), which can happen due to the heart defect itself or as a result of scarring from previous heart surgery.

Swelling of the hands, feet, legs and abdomen may be a sign of heart failure at any age.

Cyanosis (a blue tinge to the skin) occurs when blood that is poor in oxygen mixes with oxygen-rich blood. This can occur as a result of a heart defect that allows blood to flow in the wrong direction. The heart diagram below shows normal blood flow in the heart.

heart defects and blood flow

What does it mean if my child has a heart murmur?

Sometimes the heart may produce an unusual sound due to noisy blood flow. Murmurs can be heard with a stethoscope. Most murmurs are quite innocent and do not indicate a major problem. But occasionally, murmurs are a sign of a serious heart problem and so should be checked out. A heart murmur in someone experiencing symptoms such as breathlessness is more likely to be significant.

What causes congenital heart defects?

Heart defects are usually a chance occurrence due to a slight fault in the complex development of the heart. It is possible for a heart defect to be inherited, and some heart defects are more common among people with certain conditions, such as Down syndrome.

Having type 1 or type 2 diabetes can increase the risk of your baby having a heart defect. However, you can lower the risk by controlling your blood sugar levels while you are pregnant. Gestational diabetes (diabetes that develops during pregnancy) is not associated with an increased risk.

Some infections during pregnancy, such as rubella, can damage the developing heart. Most people are immunised against rubella as part of their routine childhood vaccinations.

Taking some medicines during pregnancy, such as lithium, ACE inhibitors, and isotretinoin, may cause heart defects. It’s important to check with your doctor before taking any medication during pregnancy. Smoking and drinking alcohol during pregnancy may also increase your baby’s risk of some congenital heart defects.

What are the types of congenital heart defects?

There are several different types of heart defect – some are simple and others are complex. Heart defects can affect different parts of the heart, including the walls of the heart, the valves and the main blood vessels leaving the heart. Some examples of congenital heart defects are listed below.

Holes in the heart

Holes in the heart occur in the septum – the dividing wall between the right and left chambers of the heart. An atrial septal defect (ASD) is when the hole is in the area of the septum separating the 2 atria (upper heart chambers). A ventricular septal defect (VSD) is when there is a hole between the ventricles (lower heart chambers). These holes allow blood to flow in the wrong direction through the heart and can cause cyanosis.

Small septal defects often cause no symptoms and many heal as the child grows. Larger septal defects are less likely to close on their own and usually need to be treated.

Problems with heart valves

Heart valve stenosis is significant narrowing of a heart valve. It means the heart has to work a lot harder to pump blood through the narrowed valve. Pulmonary valve stenosis is the most common congenital heart valve defect. Aortic valve stenosis is an uncommon congenital heart defect.

Heart valve regurgitation, or incompetence, is when one or more valves do not close properly, allowing blood to flow backwards. These leaky valves also put an extra load on the heart. Ebstein’s anomaly is malformation and incompetence of the tricuspid valve (on the right side of the heart).

Tricuspid atresia is when the tricuspid valve doesn’t form properly and there is no passage for blood to flow through.

Problems with blood vessels

Coarctation of the aorta is abnormal narrowing of the aorta – the main artery leaving the heart.

Before birth, a duct or channel between the aorta and pulmonary artery allows blood to bypass the lungs, which have no function while the baby is still in the womb. This channel (called the ductus arteriosus) normally closes at birth. Patent ductus arteriosus is when the channel remains open, which has a similar effect to that caused by a hole in the heart.

Transposition of the great arteries is a defect where the pulmonary artery and the aorta develop on the wrong sides of the heart, effectively swapping places.

Complex or multiple heart defects

Tetralogy of Fallot is the most common complex congenital heart defect. It consists of several heart defects, including:

  • pulmonary valve stenosis;
  • a large ventricular septal defect (VSD);
  • right ventricular hypertrophy (thickening of the heart muscle); and
  • what is known as an overriding aorta, where the aorta is located directly over the VSD, allowing oxygen-poor blood from the right side of the heart to flow into the aorta.

Complications of heart defects

There are several complications that can arise in people with congenital heart defects. These include:

  • heart failure, where the heart is not able to pump efficiently enough to meet the body’s needs;
  • pulmonary hypertension, where the blood pressure in the pulmonary arteries (the blood vessels that carry blood from the heart to the lungs) is higher than normal;
  • infective endocarditis (infection of the inner lining of the heart or the heart valves);
  • abnormal heart rhythms (arrhythmias); and
  • problems with growth and development in children.

Tests and diagnosis of congenital heart disease

Congenital heart disease can be diagnosed at any age – from the time your baby is still in the womb to adulthood.

Routine pregnancy ultrasound scans at about 18 weeks sometimes detect problems with the baby’s heart. If a defect is found, your doctor may recommend a fetal echocardiogram – a special ultrasound scan of the baby’s heart. Diagnosing a heart defect before the baby is born means that your baby will receive the appropriate treatment earlier.

In infants, older children and adults, your doctor will ask about the symptoms and perform a physical examination, including listening to the heart with a stethoscope.

Tests that can help in the diagnosis of congenital heart defects include:

  • Chest X-ray, which can show the size of the heart and whether there are any signs of heart failure.
  • Electrocardiogram (ECG) – a simple test that measures the electrical activity of the heart. A stress ECG, or exercise stress test, is an ECG done during exercise to see the effects of exertion on your heart.
  • Echocardiogram – a special ultrasound scan of the heart that can show blood flow, whether the heart valves are working normally and how the heart is functioning. A stress echocardiogram can show the effect of exercise on the heart.
  • Pulse oximetry measures the amount of oxygen in your blood through a sensor device that is clipped to one of your fingers.
  • Cardiac magnetic resonance imaging (MRI) can provide detailed images of heart defects.
  • Cardiac catheterisation is a test where a thin, flexible tube called a catheter is placed in a blood vessel (usually a vein in the groin) and then threaded up to the heart. The catheter can assess the pressure and blood flow in the chambers of the heart. Blood samples to measure the amount of oxygen in the blood can be taken from each heart chamber. Contrast dye can be injected through the catheter and X-ray images taken of the heart and blood vessels. Some heart defects can also be treated during cardiac catheterisation.

Babies and children with congenital heart defects will be referred to a paediatric cardiologist (heart specialist for children) and/or a heart surgeon. Most people with congenital heart disease need to have ongoing care with a cardiologist throughout their lives.


Treatment for congenital heart defects will depend on the type of defect and how severely it is affecting the function of the heart. Some people don’t need any treatment. For example, small holes in the heart often cause no symptoms or problems and heal on their own with no treatment.

For those who do need treatment, medicines, surgery or less invasive procedures may be recommended to repair the defect and improve the function of your heart. Sometimes several procedures or surgeries are needed over time to repair the heart defect.


Medicines can be taken to:

  • help the heart pump effectively;
  • lower blood pressure;
  • reduce the heart rate or treat abnormal heart rhythms;
  • prevent blood clots; or
  • reduce fluid overload in heart failure.

Medicines may be the only treatment needed for some simple congenital heart defects, while others may need medication to help the heart while they are awaiting or recovering from surgery.

Non-surgical procedures

Many simple heart defects, such as atrial septal defects (a type of hole in the heart) or narrowed (stenosed) heart valves can be treated with non-surgical procedures done via cardiac catheterisation.

During cardiac catheterisation, a thin tube is inserted into a blood vessel (usually in the groin) and threaded through to the heart under X-ray or ultrasound guidance. Tiny instruments or devices can be inserted via the thin tube (catheter) and used to repair some heart defects.


With serious heart defects, surgery may be the best treatment. Surgery can be carried out soon after birth, if necessary.

For any operation inside the heart, the heart must be stopped and emptied of blood to enable the surgeon to repair the defect. This is open heart surgery and requires a heart-lung machine to carry out the work of the heart and lungs.

Minimally-invasive heart surgery may be an option for repairing some heart defects. This involves several small cuts instead of a large incision to open up the chest.

In rare cases, heart transplants may be recommended for children with defects that are life-threatening and cannot be repaired.

Fetal surgery

Some specialist centres are starting to develop procedures to treat heart defects in babies while they are still in the womb. However, these procedures are not commonly performed at the moment, and are only an option for a small number of conditions. The risks for the mother and baby need to be weighed against the benefit of early treatment during pregnancy. Talk to your paediatric cardiologist about developments in this area.

Living with congenital heart disease

While it’s usually possible to treat congenital heart defects, lifelong follow-up with a cardiologist is usually needed to make sure that you remain healthy. Monitoring your condition and taking some simple precautions are often all that’s needed, but sometimes further treatment is needed after several years. Lifestyle adjustments may be recommended to reduce symptoms or the risk of complications, even after treatment or repair.

Physical activity

Young children with heart troubles don’t usually overtax themselves. It is, therefore, often unnecessary to try to restrict their physical activities. With some older children, over-strenuous exertion may need to be avoided, but many children with congenital heart disease have no or few restrictions on their physical activities. Your doctor will let you know which activities are recommended or best avoided. The aim is for your child to live as full and normal a life as possible.

Some teenagers and adults with congenital heart disease may also need to limit some activities – your cardiologist will be able to advise you.

Risk of infection

People with heart defects are at increased risk of developing endocarditis – an infection of the inner lining of the heart and heart valves. This is usually caused by bacteria, and can lead to serious problems, including heart valve damage and stroke.

To reduce the chances of developing infective endocarditis, take the following precautions.

  • If your child develops an infection, such as a chest infection, see your doctor to check whether antibiotics may be needed.
  • Keep your teeth and mouth healthy, as this can be a source of bacteria that may spread to the heart. Regular 6-monthly dental checks are essential. Antibiotics must be given when extractions and other dental work is being done.
  • Immunisation is always advisable but is even more important for someone with a heart defect. Immunisations are usually given according to the normal schedule.

Pregnancy in adults with congenital heart defects

Many women with congenital heart defects are able to have uncomplicated pregnancies. However, some women with complex heart defects may be at risk of serious health problems if they become pregnant. Your doctor will be able to advise you on whether you are at risk of pregnancy complications and whether special care would be needed during pregnancy. Your doctor may also suggest extra prenatal tests to check your baby’s heart.

Can congenital heart defects be prevented?

Most congenital heart defects have no known cause and could not have been prevented. However, there are some things that can be done to help reduce the risk of congenital heart defects.

If you are planning a pregnancy, make sure that your immunisations are up to date, and that you have been immunised against rubella. A simple blood test can check whether you are immune to rubella. If you are taking regular medicines, ask your doctor if they are safe to take during pregnancy. Start taking a folate (folic acid) supplement, which can reduce the risk of spina bifida, and possibly also heart defects. Recent studies have indicated that Vitamin B3 (niacin) supplements may also help prevent congenital heart defects in some people.

During pregnancy, continue supplements as directed by your doctor. Don’t take any medicines or supplements during pregnancy without checking with your doctor first, and avoid smoking and drinking while you are pregnant. If you have diabetes, work with your doctor to keep your blood sugar levels in the optimum range.

Support groups

Support groups are available for people with congenital heart defects and their families. Being able to meet other people with similar problems can help immensely. Talk to your doctor or search the internet to find out what support groups are available in your area.

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