Cardiac screening tests

Cardiac screening tests are used to assess if your child has an inherited cardiovascular condition and also provide us with measurements of improvement, stability or deterioration for children who have a condition. You are able to stay with your child during all the tests. Your child will have an electrocardiogram (ECG) to look at the electrical signal of the heart, and an echocardiogram (Echo), an ultrasound scan of the heart. They may also require an exercise test to assess the rhythm and function of their heart at a faster rate. We may also need to perform additional investigations, which may include blood tests, having a 24-hour ECG monitoring (Holter), and magnetic resonance imaging (MRI) scan of the heart.

• An ECG records the electrical signal as it is conducted throughout the heart. It is a simple test performed by placing sticky electrodes on the child’s chest, legs and wrists. An ECG is entirely safe, takes a few minutes and causes no pain, although the child may be anxious about the stickers and connecting wires.
• An Echo is an ultrasound scan of the heart. A picture of the heart is produced from which an accurate assessment of the size and function of the heart can be made. The scan takes from 30 to 40 minutes. As before this test is not painful, but children sometimes find the jelly on the probe a bit uncomfortable. Children can watch their favourite videos during the scan.
• An MRI scan uses a magnetic field rather than x-rays to take pictures of your child’s body. The MRI scanner is a hollow machine with a tube running horizontally through its middle. Your child will lie on a bed that slides into the tube. An MRI scan usually lasts between 20 minutes and an hour. Please watch our short video film about having an MRI.
• A 24-hour ECG recording (or Holter) uses a small box similar in size to a portable stereo, from which three leads are attached by sticky pads to your child’s chest. This is an ECG monitor that continuously records the heartbeat over 24 to 48 hours. Children wear the monitor under their clothes and can continue with their normal daily life including sport and exercise. You and your child will be asked to document your child’s activities during the 24 to 48 hour period to match with the recording when the box is analysed. When the test is finished, you will be required to return the monitor to GOSH so that the results can be analysed.

• An exercise test is a specially modified test that assesses the rhythm and function of the heart at a faster rate, while the child is on an exercise bicycle or a treadmill. Blood pressure and breathing are also monitored during the test. This test is usually only performed on children over the age of eight years due to their size. Exercise testing also provides us with an objective measurement of improvement, stability or worsening of heart function over time. The test takes approximately 45 minutes and allows symptoms not obvious at rest to become apparent when the heart is working harder. We recommend children to wear loose comfortable clothing for the test.
• Electrophysiological studies are a special type of cardiac catheterisation used to study the electrical activity of the heart in detail. It is needed when a potentially more serious abnormal heartbeat is suspected. This procedure will involve your child having a general anaesthetic.
• A tilt test helps to understand fainting spells and involves lying on a table which is then tilted into various positions.
• An ajmaline test is very similar to an ECG except that your child is given an injection of a medicine called ajmaline, which brings about changes on the ECG that can help us to diagnose a specific condition called Brugada syndrome. The medicine is given through a cannula (thin plastic tube) during which your child’s heart rate is closely monitored for changes over a period of 15 minutes.

After your cardiac screening tests are completed you will see the consultant and clinical nurse specialist at your consultation. The results will be given and discussed with you. We will send a copy of the clinic letter to you and your child’s GP. At the end of the consultation the team will discuss with you when they want to see your child again and if so, approximately when.

We hope you will feel able to ask questions of any member of the team about anything you do not understand. It is important to ask questions and to make sure you get explanations in language that you understand. When you see the team in clinic you may find it useful to take in a list of questions you want to ask.

Once your child has had all the screening tests, the team will look at the results to try to reach a diagnosis. They will explain the diagnosis and what happens next. Most conditions will require regular life-long monitoring and some may need treatment with medicines or surgery or both.