Congenital heart defects
What is the function of the heart?
The heart is a pump and its main function is to pump blood around the body. It is separated into left and right sides by a muscular partition (septum). The left side of the heart pumps red blood containing oxygen and other fuels through the main artery, or aorta, to the arteries of all parts of the body.
Tissues in the body, such as muscle, brain and kidneys, use some of the oxygen in the blood, leaving it with a blue tinge. The ‘blue’ (deoxygenated) blood returns in the veins to the right side of the heart which pumps it through the pulmonary arteries to the lungs. Here, the blood receives oxygen again, restoring its red colour, and returns to the heart ready to be pumped once more through the body.
Each side of the heart has a receiving chamber (the atrium) and a pumping chamber (the ventricle). As with any pump, valves are necessary to keep the flow in the proper direction and each side of the heart has 2 valves, one at either end of the ventricle. The right-sided valves are called the tricuspid and pulmonary valves and the left-sided valves are called the mitral and aortic valves.
What is a congenital heart defect?
The word congenital means ‘from birth’, so a congenital heart defect usually results from a fault in development in the first few weeks of pregnancy. In Australia, as many as one baby in 100 is born with a heart defect.
Many of the defects are trivial, producing no problems throughout life. Others are more serious, requiring surgical correction, while a few cannot be corrected.
Why do congenital heart defects occur?
Heart defects are usually a chance occurrence due to a slight fault in the complex development of the heart. It is rare for a heart defect to be inherited, that is, to occur because of faulty genes from either parent.
One known specific cause of congenital heart disease is the rubella (German measles) virus, which can damage the developing heart. A mother who comes in contact with rubella during pregnancy should consult her doctor.
Some drugs may cause heart defects, so no medication should be taken in early pregnancy, except on a doctor's recommendation. Things such as getting a bad fright or having an accident or a threatened miscarriage do not cause congenital heart defects. Babies are well protected in the womb from most outside influences.
What types of heart defect are there?
Here are some of the main types of congenital heart defects.
Stenosis
This is a significant narrowing of a heart valve. It means the heart has to work a lot harder to pump blood through the narrowed valve.
Coarctation
Abnormal narrowing may also occur in the aorta. It is corrected surgically.
Regurgitation
Also called incompetence: this is when one or more valves do not close properly, allowing blood to flow back into the heart chamber, which puts extra load on the heart. Surgery may be needed if the valve defect is severe.
Holes in the heart
Holes within the heart may occur in the muscular partition between the atria (an atrial septal defect) or the partition between the ventricles (a ventricular septal defect). These holes allow an abnormally large amount of blood to flow into the right side of the heart and through the lungs.
If the hole is very large, surgery may be required in infancy. Children with large heart defects will easily get breathless, have a tendency to get chest infections and will not put on weight easily.
Those with smaller holes will often make satisfactory progress and surgery can be postponed. In some cases of ventricular septal defect, the hole may become smaller as the child grows older so an operation may be avoided altogether.
Patent ductus arteriosus
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 normally closes at birth but if it doesn't, the effect is similar to that caused by a hole in the heart. It is relatively easy to correct.
Blue babies
There are a number of more complicated defects in which some ‘blue’ and red blood mixes. Blueness (cyanosis) may not be present all the time but any baby who becomes blue and breathless needs to have his or her heart checked urgently. Heart disease that causes cyanosis cannot get better on its own, but in most cases the defect can be detected by ultrasound and corrected surgically.
What does it mean if my child has a heart murmur?
Sometimes the heart may produce an unusual sound due to noisy blood flow. These so-called 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 intermittent blueness, breathlessness on exercise, or fainting is more likely to be significant.
What tests may be required?
In most cases a medical examination with an X-ray of the heart, an electrocardiogram (ECG) and an echocardiogram will be enough to decide if a heart defect requires treatment.
Sometimes cardiac catheterisation is necessary. In this test, carried out under anaesthetic, special tubes are passed through an artery and/or vein to take a variety of recordings and X-rays of the heart. This will provide the cardiologist and heart surgeon with detailed knowledge of the structure of the heart so they can decide on the best form of treatment.
What treatment is required?
With serious defects, surgery can now be carried out, if necessary, in the first week of life. Where possible, however, operations are usually postponed until the child is older.
With some of the simpler defects, surgery can be carried out while the heart is still beating. For any operation inside the heart, however, the heart must be stopped and emptied of blood to enable the surgeon to repair the defect.
A heart-lung machine is used during the operation to carry out the work of the heart and lungs. The heart may take some time to recover from the effects of surgery but many children can go home within one to 2 weeks of the operation. Some patients (such as those with a hole in the heart) may require medication to help the heart while they are awaiting or convalescing from surgery.
Young children with heart troubles don't usually overtax themselves. It is, therefore, often unnecessary to try to restrict them. With older children, over-strenuous exertion is best avoided. Competitive athletics or sports such as rugby are generally unwise, but the child can usually play socially in the playground and can often enjoy non-competitive tennis, physical education and swimming.
Your doctor will specify which activities are permitted. The aim is for the child to live as full and normal a life as possible. Usually, no restrictions at all are necessary for children with innocent murmurs.
However, children with heart defects such as leaky valves do need special care if they develop infections such as bronchitis, pneumonia, tonsillitis, infected sores or boils. Bacteria can spread to the heart, causing bacterial endocarditis. A doctor should be consulted to decide if treatment with antibiotics is indicated.
Bad teeth are a particularly common source of trouble. Regular 6-monthly dental checks are essential and the dentist must know that your child has a heart defect. An antibiotic must be given when extractions and other major dental procedures are being carried out.
What about childhood illnesses?
Common illnesses such as measles and chickenpox present no particular risk to a child with a heart defect, although a check from your doctor is a wise precaution whenever your child is ill. Children with heart defects are NOT at higher risk of cot death.
Should your child be immunised?
Immunisation is always advisable but is even more important for a child with a heart defect. Immunisations are usually given according to the normal schedule, and will only be postponed if the child is very ill.
Does a heart defect produce other problems?
Physical development may be slow in a child who has been ill because of his/her heart, but this will usually improve once the heart defect is corrected. Sometimes a heart defect may be associated with other congenital problems, but your doctor will check this possibility. Parents are often concerned that a heart problem may slow mental development, however, this is rarely the case.
Should you tell your child about his/her heart?
Explain the condition to your child in simple, clear terms and encourage them to tell you if they are feeling any changes or if they have any questions or worries about their condition, or any treatment they are having. Children readily accept these things.
If they are going into hospital, explain why, tell them who they will meet there, and reassure them that you will be with them. A couple of days' warning is enough for a young child.
Will a child with a heart defect be able have children when they are older?
Most patients with minor defects, and many of those who have undergone surgery for important defects, can look forward to raising a family. Although there have been some exceptions, most children of patients with congenital heart disease have normal hearts.
A final word of advice
Bringing up a child with a heart defect requires no special knowledge or wisdom, just common sense. If you need advice, get it from your doctor.
Advice from well-meaning friends and relatives is often based on a mixture of hearsay and half-truths that may be more confusing than helpful. Every effort should be made to avoid undue emphasis on the child's disability but other children can be educated to accept any limitations with understanding.
Last Reviewed: 10 April 2009
