Back to fact sheets
Print Friendly, PDF & Email
Children’s Health Queensland Hospital and Health Service Children’s Health Queensland Hospital and Health Service

Congenital heart defect fact sheet

Congenital heart defect

A congenital heart defect (CHD) is a defect in the structure of the heart and great vessels which is present at birth. Many types of heart defects exist, most of which either obstruct blood flow in the heart or vessels near it, or cause blood to flow through the heart in an abnormal pattern. Other defects, such as long QT syndrome, affect the heart’s rhythm.

Heart defects are among the most common birth defects and are the leading cause of birth defect- related deaths. 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.


To help find out what is wrong with your child, the 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.


This is a routine test that uses ultrasound to give 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. Certain cardiac conditions can be corrected by cardiac catheterisation. These are called interventional catheters. These catheters can correct an ASD (atrial septal defect), PDA (patent ductus arteriosis) or be used to balloon narrow valves and blood vessels. 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. The MRI uses painless magnet waves to evaluate the heart and the blood vessels connected to the heart and lungs. Often your medical team will need to place a small IV in your hand. The test usually takes 30-60 minutes to perform, and you must be perfectly still for 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 center of the magnet. This can be disturbing even for adults, but many centers have special headphones and video masks that can help to keep you 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 oesophagus, while your child is under anaesthetic.

Your cardiologist may recommend a TOE when the standard echocardiogram isn’t clear enough to make the suspected diagnosis or if you are 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 prior to leaving the operating room. The risk of a TOE is minimal.

Computerized tomography (CT) scan

The CT scan uses multiple X-ray images to take an X-ray movie of the heart and lungs without placing catheters into the circulation. Like the MRI, this test sometimes takes clearer pictures than an angiogram. The test only requires a simple IV in the hand, and it can be done more quickly than an MRI. Unlike MRI imaging, the CT scan uses about the same amount of X-ray as is needed for an angiogram. Again, your cardiologist can arrange an anaesthetic for your child to minimize anxiety during the test.

Contact us

Queensland Paediatric Cardiac Service
Queensland Children’s Hospital
501 Stanley Street, South Brisbane
t: 07 3068 1765
t: 07 3068 1111 (general enquiries)

In an emergency, always call 000.

If it’s not an emergency but you have any concerns, contact 13 Health (13 43 2584). Qualified staff will give you advice on who to talk to and how quickly you should do it. You can phone 24 hours a day, seven days a week.

Resource No: FS088. Developed by Queensland Paediatric Cardiac Service. Updated: February 2015. All information contained in this sheet has been supplied by qualified professionals as a guideline for care only. Seek medical advice, as appropriate, for concerns regarding your child’s health.