Congenital heart defects

A congenital heart defect (CHD) is a defect in the structure of the heart and/or its vessels which is present at birth.

There are many types of heart defects, most of which either obstruct blood flow to or in the heart, or cause blood to flow through the heart in an abnormal pattern. Other defects can affect the heart’s rhythm.

Heart defects are among the most common birth defects. Approximately one in every 100 children is born with a congenital heart defect. Many defects don’t need treatment, but some complex congenital heart defects require medication or surgery.

How is a congenital heart problem diagnosed?

Some very serious congenital heart defects may be diagnosed by ultrasound during pregnancy. However, most are usually diagnosed during infancy, and others during childhood or even in adulthood, by some simple tests.

Tests

To help find out what is wrong with your child, a cardiologist will ask about your child’s medical history, do a physical examination and usually arrange some tests, such as an electrocardiogram (ECG), a chest X-ray, an echocardiogram or cardiac catheterisation (see below). After reviewing all of the information and test results, the cardiologist will talk with you about your child’s health. If your child has a heart problem, the cardiologist will explain how to manage or treat the problem.

Chest X-rays

The chest X-ray gives the cardiologist information about your lungs and the heart’s size and shape. The amount of radiation from a chest X-ray is extremely small and doesn’t cause any long-term side effects.

Electrocardiograph (ECG)

An ECG is a test that shows doctors how the heart’s electrical system is working. During an ECG, electrical leads are placed on your child’s chest, arms and legs. These leads detect small electrical signals and produce a tracing on graph paper that illustrates the electrical impulses travelling through the heart muscle. ECGs are harmless and painless.

Echocardiogram

This is a routine test that uses ultrasound to create a picture of your child’s heart, including its chambers and valves. Echocardiograms are usually done in semi-darkness. Your child will need to stay very still so that the picture will be clear. Like an ECG, an echocardiogram is also painless and harmless.

Cardiac catheterisation and angiogram

A cardiac catheterisation is a procedure that allows the cardiologist to get direct information about the blood pressures and patterns of blood flow within your heart. An angiogram is an X-ray movie that’s taken while contrast (a special fluid that’s visible by X-ray) is injected into a cardiac chamber or major blood vessel. Some medications will need to be ceased one week before this test is performed.

Magnetic resonance imaging (MRI)

Magnetic resonance imaging is another way to take clear pictures of the heart and measure heart function. An MRI uses painless magnetic waves to evaluate the heart and the blood vessels connected to the heart and lungs. The test usually takes 30-60 minutes to perform, and your child must lie perfectly still during the test.

During the test the child lies on a table within the magnet. Most of the body will be within a small tunnel in the centre of the magnet. This can be a bit scary, even for adults, but many centres have special headphones and video masks that can help to keep children calm during the test. If needed, your cardiologist can arrange an anaesthetic for your child to minimize anxiety during the test.

Transesophageal echocardiogram (TOE)

A transesophageal echocardiogram or TOE is a special type of ultrasound movie of the heart that produces much clearer pictures than a standard echocardiogram that’s performed on your child’s chest. To complete the study, the doctor places a special long tube with a small ultrasound probe on the end, called a TOE probe, in your child’s oesophagus, while they are under anaesthetic.

Your cardiologist may recommend a TOE when the standard echocardiogram isn’t clear enough to make the suspected diagnosis or if your child is having heart surgery so the surgeon and anesthesia team have more information to guide treatment after surgery. The TOE also helps the surgical team determine whether the procedure has been successful or if additional repair is needed before leaving the operating room. The risk of a TOE is minimal.

Computerized tomography (CT) scan

A CT scan uses multiple X-ray images to create a video of the heart and lungs. A CT scan sometimes takes clearer pictures than an angiogram and can be quicker than an MRI.
The CT scanner looks like a big doughnut. For the scan, your child will need to lie on a table that moves through the middle of the doughnut and try to stay still. Your cardiologist can arrange an anaesthetic for your child if they are feeling anxious.

Resource ID: FS093. Reviewed: October 2023. Developed by Queensland Paediatric Cardiac Service. We acknowledge the input of consumers and carers.

Disclaimer: This information has been produced by healthcare professionals as a guideline only and is intended to support, not replace, discussion with your child’s doctor or healthcare professionals. Information is updated regularly, so please check you are referring to the most recent version. Seek medical advice, as appropriate, for concerns regarding your child’s health.