Congenital heart disease

What is congenital heart disease?

Abnormalities or defects of the heart which develop before birth are together (collectively) called congenital heart disease. This is a general 'umbrella' term which covers many different heart problems. Some of these are listed in the section below.

Different parts of the heart can be affected. To understand the parts of the normal heart, see the separate leaflet called Heart Disease, or watch the video from the British Heart Foundation in the 'Further Reading' section at the end.

Generally speaking, the defects in congenital heart disease affect the way the blood flows through the heart in some way. They are usually due to an abnormality of the structure of the heart.

Congenital heart disease can affect babies throughout their lives. Even after treatment for a congenital heart defect, there may be health implications once they are adults.

What kinds of congenital heart disease are there?

In the different conditions, the defect is in different parts of the heart. The problem can be with the chambers of the heart, the valves of the heart, or the blood vessels of the heart. There is a big range in how severe the conditions are - from mild to life-threatening.

There are many types of congenital heart disease defects. These are some of the more common ones:

• Ventricular septal defect (VSD). This is a hole in the wall (septum) between the left and the right ventricles (chambers) of the heart. It is the most common type of congenital heart defect. This condition is fully explained in the separate leaflet called Ventricular Septal Defect (Hole in the Heart).

• Atrial septal defect (ASD). This is a hole in the wall (septum) between the two upper chambers of the heart (the left and right atria). Before birth, there is a connection between the two, called the foramen ovale. This normally closes after birth. If it does not close, blood can pass from the left atrium to the right. This over time gradually puts extra pressure on the right side of the heart. This condition is fully explained in the separate leaflet called Atrial Septal Defect.

• Patent ductus arteriosus (PDA). The ductus arteriosus is a tube which connects the two main arteries of the heart (the pulmonary artery and the aorta). This connection is important when the baby is in the womb, but after birth it closes off. If it does not close, it remains open (patent) and the result is too much blood going to the lungs, causing congestion in the lungs.

• Abnormalities of the heart valves. Blockage of blood flow at or near the valves of the heart causes problems for the circulation and puts extra pressure on certain parts of the heart or lungs. Valves may be abnormally shaped or narrowed (stenosis) or in some cases absent (atresia). Examples of these conditions include:

  • Aortic stenosis.

  • Bicuspid aortic valves.

  • Pulmonic (or pulmonary) stenosis.

  • Mitral stenosis.

  • Pulmonary atresia.

  • Tricuspid atresia.

  • Ebstein's anomaly.

• Coarctation of the aorta. This is a narrowing of the aorta, the large blood vessel through which blood leaves the heart. If it is narrow, the heart has to work much harder to squeeze the blood through. This causes high blood pressure, difficulty getting blood to all areas of the body and a part of the heart to become abnormally large. This condition is fully explained in the separate leaflet called Coarctation of the Aorta.

• Atrioventricular septal defect (endocardial cushion defect). This can be partial or complete. It is another problem involving holes in the internal wall (septum) or walls between the chambers of the heart. There is a hole (defect) involving the atrial septum, ventricular septum and one or both of the valves between the atria and ventricles (atrioventricular valves).

• Fallot's tetralogy (or the tetralogy of Fallot). In this condition, there are four heart defects together. These are:

  • A ventricular septal defect (VSD).

  • A narrowed pulmonary valve (pulmonary stenosis).

  • One of the chambers of the heart - the right ventricle - is enlarged (right ventricular hypertrophy).

  • The aorta is positioned in such a way that it takes blood from both the left and right sides of the heart, instead of just the left (called an over-riding aorta).

• Transposition of the great arteries. In this condition, there is an abnormal arrangement of the main blood vessels leaving the heart. This results in blood pumping round and round the body without ever going through the lungs. Unless the ductus arteriosus stays open, no oxygenated blood gets round the body, so it is very urgent to treat this quickly after birth.

• Hypoplastic left heart syndrome. In this condition, the left side of the heart is small and severely underdeveloped.

There are so many congenital heart defects that it is beyond the scope of this leaflet to fully describe each one individually. If you or your child have a congenital heart defect, your heart specialists will be able to give you plenty of information about the individual condition, both by explaining it and by giving you information to read. This will then be relevant to you specifically. The British Heart Foundation also has a series of leaflets about many of the more common congenital heart defects. (See in the 'Further Reading' section below.)

Non-cyanotic and cyanotic congenital heart disease

You may see the types of congenital heart disease divided into two groups: cyanotic and non-cyanotic. Cyanotic means a blueish colour of the skin. This happens when oxygen levels are low. So the cyanotic types of congenital heart disease cause low oxygen levels in the blood. Normally, the blood pumped around the body by the heart goes through the lungs. If the heart defect is such that blood bypasses the lungs, the body doesn't get enough oxygen.

Why does congenital heart disease occur?

Something goes wrong during the development of the heart while the baby is in the womb. It is not fully understood why a congenital heart defect happens in many cases. Many are due to genetic abnormalities - changes in the baby's genes. The following risk factors can make congenital heart disease more likely to happen:

• Someone else in the family has congenital heart disease.

• The parents of the baby are closely related (eg, they are cousins).

• The mother of the baby had rubella whilst pregnant.

• The mother of the baby has had excessive amounts of alcohol while pregnant or used recreational drugs or certain medicines such as lithium.

• The mother of the baby has diabetes.

• The mother of the baby is overweight.

• The baby has another genetic condition such as Down's syndrome, DiGeorge syndrome or Turner syndrome

How common is congenital heart disease?

In Europe, about 8 babies in every 1,000 babies born have a congenital heart defect. In the UK, this means approximately 12 babies every day are diagnosed with a congenital heart defect. Worldwide, figures vary. There are slightly more babies born with congenital heart defects in Asia, and slightly fewer in North America.

Congenital heart disease tests

A congenital heart defect is often picked up before any symptoms develop. Many types of congenital heart disease are seen on the ultrasound scans women have during pregnancy. Babies in the UK have a full medical examination at birth and at 6 weeks of age, and part of this involves a doctor checking pulses in the baby's groin and listening to the heart for any abnormal sounds which might indicate congenital heart disease. If anything unusual is noticed then a specialised ultrasound scan of the heart (echocardiogram, or 'echo') is arranged. This can be done either before or after birth.

Other tests which may be helpful include:

• Checking the oxygen levels by a device on your baby's thumb, finger or toe (pulse oximeter) or through a blood test.

• Other blood tests.

• A chest X-ray.

• A heart tracing (electrocardiogram, or ECG).

Congenital heart disease symptoms

As described above, congenital heart disease is often picked up during screening before any symptoms develop. A mild congenital heart defect may not cause any symptoms at all, or may not cause any problems until adult life. At the other end of the spectrum, the baby may have life-threatening problems as soon as they are born. The symptoms depend on the exact defect but some possible symptoms include:

• Difficulty breathing.

• Difficulty feeding.

• A blue colour to the skin, either all the time, or while crying.

• Slow or less-than-normal growth.

• Swellings due to fluid overload (where the heart pump is not working as well as it should). Fluid can accumulate around the eyes, in the legs or around the tummy area.

• Tiredness.
  

Congenital heart disease treatment

Treatment depends on the specific defect. Some mild congenital heart defects don't need any treatment, and some (such as small holes in the internal heart walls) may even correct themselves. However, many children with congenital heart disease need an operation. Some need more than one operation. This is to try to correct the abnormality and allow the heart to function as it should. Usually this is an open operation but sometimes smaller keyhole procedures can be done via an artery. In very severe defects, sometimes only a heart transplant can correct the problem.

Babies may need special feeds if they are not growing well. Sometimes medicines help, either instead of an operation, or before an operation is done. Medicines can help the body clear any fluid overload, for example, or return the pulse rate to normal or settle high blood pressure. A type of medicine called a prostaglandin is sometimes needed for some defects after birth to keep the ductus arteriosus open to allow blood with oxygen to reach the circulation until an operation can be done.

In some cases, treatments and/or monitoring may be needed for life.

What are the complications from congenital heart disease?

This depends on how severe the congenital heart defect is. Possible complications can include:

• Not growing and/or developing as well as other children. This can mean being smaller, and/or being slower to reach development 'milestones'. Children with congenital heart disease are more likely to have learning disabilites.

• An increased risk of infective endocarditis. This is an infection of the inner lining of the heart, which can cause damage to the heart valves. Most types of congenital heart disease increase the risk of this condition.

• Not being able to do as much exercise as other children/adults. Exercise capacity may be limited by breathlessness or tiredness. In very severe cases, strenuous exercise may not be safe.

• An increased risk of chest infections.

• An increased risk of blood clots and strokes.

• Pulmonary hypertension. This is a knock-on effect where there is an increase in the pressure of the arteries of the lungs. This can occur in congenital abnormalities where the blood of the left side of the heart can pass directly to the right side of the heart. More blood than normal then passes from the right side of the heart to the lungs, putting them under too much pressure. Over time, this in turn causes a raised pressure in the right side of the heart, causing the left-to-right shunt to swap to a right-to-left shunt. This is called Eisenmenger's complex. If this happens then blood which has not been through the lungs to pick up oxygen gets sent back into the circulation. The non-cyanotic type of congenital heart disease then becomes a cyanotic type.

• Problems with heart rate and rhythms. Some heart problems may cause palpitations or may cause the heart to beat too slowly, too fast, or in an erratic way. Some abnormal rhythms can be very dangerous and even cause death.

• A risk of heart failure.

Congenital heart disease in adults

For mild congenital heart defects there may be very little effect into adult life. For others, lifelong treatment may be needed. Ongoing issues (as well as the risks discussed above) include:

• Less ability to exercise, with a knock-on effect on general health, weight, well-being and quality of life

• Pregnancy. It may not be safe for some women with severe congenital heart disease to become pregnant. It is very important to discuss pregnancy with your specialist BEFORE becoming pregnant if you have a history of congenital heart disease. Depending on your specific heart condition it may be very risky, and for some women there will be a high risk of dying. For many others, it will be safe to become pregnant, but changes to medication may be needed, or extra monitoring.

• Contraception. Particularly if pregnancy would be dangerous for a woman, contraception is extra-important. It is an issue which should be discussed with your doctor and specialist. Some types of contraception, particularly the combined oral contraceptive pill, may not be advisable in some cases of congenital heart disease. It depends on the exact condition you have. Your doctor will be able to advise.

• Reducing the risk of endocarditis. Because dental problems and infections can be a source of infection, good oral hygiene is particularly important if you have congenital heart disease. (Antibiotics are no longer recommended routinely when having dental procedures, however.) Also there is thought to be more of a risk following tattoos and body piercings, so people with congenital heart defects are usually advised to avoid these.

What is the outcome (prognosis)?

This entirely depends on the specific heart defect, and ranges from excellent to poor. Those with minor defects may have no problems and a normal life expectancy. However, some defects can sadly reduce life expectancy. Generally speaking, children who have had heart surgery do not live as long as children who have not. The first year of life with a congenital heart defect is the riskiest.

Your specialist will advise on your or your child's specific case.