When your child is referred to a paediatric cardiologist, you may wonder which tests they will need and what each investigation involves. Many first-line heart tests, including ECGs and echocardiograms, are non-invasive and usually well tolerated. A small number of children may need more specialised investigations involving sedation, general anaesthesia or an invasive procedure.
Some assessments may be performed by the cardiologist, while others are carried out by cardiac physiologists, echocardiographers, radiographers, nurses or other specialists and then reviewed by the cardiology team.
The cardiologist will recommend investigations according to your child’s symptoms, age, examination findings, medical history and family history. Not every child needs every test, and understanding why an investigation has been suggested can help you and your child feel more prepared for the assessment.
How Does the Cardiologist Choose the Right Tests?
The cardiologist chooses your child’s tests based on their symptoms, medical history and when those symptoms occur. They will also consider whether the symptoms are linked to activities such as exercise, feeding, or illness.
Your child’s age, family history and examination findings also help determine which investigations are appropriate. The cardiologist will usually begin with non-invasive tests and recommend more specialised investigations only when the results could clarify the diagnosis, guide treatment or monitor a known condition.
Clinical Tip
Before the appointment, note when your child’s symptoms occur, how long they last and whether they are linked to exercise, feeding, illness or rest. Bring an up-to-date medication list and relevant family history, but do not stop medicines, fast your child or restrict drinks unless the clinic has provided specific instructions.
When Should You Seek Urgent Medical Help?
Most paediatric cardiology tests are planned investigations, but do not wait for a routine appointment if your child develops severe or rapidly worsening symptoms. If your child faints and fully recovers, arrange a GP assessment to help identify the cause. Follow any emergency plan already provided by your child’s specialist team, and use NHS 111 if you need urgent advice.
Call 999 if your child is not breathing or has severe difficulty breathing, such as gasping, choking or being unable to speak normally. Also call 999 if they cannot be woken within one minute after fainting, have not fully recovered, have difficulty speaking or moving, faint during exercise or while lying down, or faint with chest pain or a pounding, fluttering or irregular heartbeat. Emergency help is also needed if they are shaking or jerking because of a suspected seizure or fit, or have seriously injured themselves.
Call 999 if your child’s lips, tongue, face or skin suddenly turn blue or grey. On brown or black skin, this may be easier to see on the palms of the hands, soles of the feet, lips, gums or inside the eyelids. If only your child’s fingers, toes, hands or feet appear blue or grey and they are otherwise responsive and breathing normally, contact NHS 111 for urgent advice.
Pulse, Blood Pressure and Oxygen Saturation Tests
These simple, non-invasive measurements provide important information about your child’s heart health and overall circulation. They are usually performed at the start of the assessment.
- Pulse rate: Measures how fast and regularly your child’s heart is beating.
- Blood pressure: Assesses the pressure of blood flowing through the arteries.
- Oxygen saturation: Uses a pulse oximeter to estimate how much oxygen the blood is carrying. The result is interpreted alongside your child’s symptoms and other examination findings.
- Height and weight: Helps assess your child’s growth and supports accurate interpretation of test results.
These measurements do not diagnose a heart condition on their own, but they help the cardiologist decide whether further investigations are needed.
Resting Electrocardiogram
A resting electrocardiogram (ECG) records the electrical activity of your child’s heart to check their heart rate and rhythm. During the test, small sticky electrodes are placed on your child’s chest, and sometimes their arms and legs, to record the heart’s natural electrical signals.
An ECG is quick, non-invasive and does not send electricity into your child’s body. It provides a brief recording of the heart’s electrical activity and may identify an abnormal heart rhythm, a problem with how electrical signals travel through the heart or another unusual electrical pattern that requires further assessment. An ECG does not, by itself, show the heart’s detailed structure or fully assess its pumping function.
Echocardiogram
An echocardiogram, or echo, is an ultrasound scan that allows the cardiac team to assess your child’s heart in real time. It shows the heart’s structure, valve movement, pumping function and blood flow without using X-rays or ionising radiation.
During the scan, a small probe is moved across your child’s chest using ultrasound gel, and you can usually stay with them. The scan is non-invasive and generally painless, although firm pressure from the probe may feel uncomfortable for some children. Your child will need to remain as still as possible so that clear images can be obtained.
When Might Sedation Be Needed for an Echocardiogram?
Most children can have an echocardiogram while they are awake. Sedation may occasionally be considered for a baby or young child who cannot remain still enough for the cardiac team to obtain reliable images. Whether it is appropriate will depend on your child’s age, health, the type of scan and the facilities available.
If sedation is planned, the team will explain its benefits and possible risks and provide specific instructions about food, drinks and medicines. Do not fast your child or stop, delay or change any medicine unless the hospital or cardiac team has specifically instructed you to do so. A routine awake echocardiogram usually requires little or no special preparation.
Holter Monitoring
A Holter monitor continuously records your child’s heart rhythm. A 24- to 72-hour monitor may be useful when palpitations, dizziness or fainting occur frequently enough to have a reasonable chance of being recorded during that period.
Your child may be asked to continue their usual activities and keep a diary of symptoms and activities so that these can be compared with the recording. Follow the cardiac team’s instructions about bathing, swimming and exercise because many monitors need to be kept dry.
Event Monitors and Longer-Term Rhythm Recorders
If your child’s symptoms occur too infrequently to be captured by a Holter monitor, the cardiologist may recommend a longer event monitor or another form of extended rhythm recording. Some devices are activated when symptoms occur, while others automatically record selected rhythm changes over several days or weeks.
If external monitoring has not captured very occasional symptoms, an implantable loop recorder may be considered. This small device is placed beneath the skin during a planned procedure and can monitor the rhythm for much longer; the team will explain its purpose, insertion, anaesthesia or pain relief, limitations, aftercare and possible risks before consent is given.
Exercise ECG or Exercise Stress Test
An exercise ECG, also called an exercise stress test, shows how your child’s heart responds to physical activity. It may be recommended when symptoms such as palpitations, dizziness, breathlessness or chest discomfort mainly occur during exercise. Whether the test is suitable will depend on your child’s age, size, ability to use the equipment and the reason for testing.
Your child will usually walk on a treadmill or use an exercise bicycle while their ECG and heart rate are monitored; blood pressure, oxygen levels or breathing may also be assessed. Follow the appointment instructions about clothing, footwear, food, drinks and medicines, and do not stop medication unless the cardiology team specifically advises you to do so.
Ambulatory Blood Pressure Monitoring
If a single blood pressure reading does not provide enough information, the cardiologist may recommend 24-hour ambulatory blood pressure monitoring. The cuff measures your child’s blood pressure repeatedly during normal daytime activities and sleep and may briefly feel tight or disturb their sleep.
You may be asked to record activities, sleep and symptoms to help the team interpret the readings. The monitor generally needs to remain dry, and the results can help distinguish persistently raised blood pressure from readings affected by the clinic environment and show how blood pressure changes overnight.
Chest X-Ray
A chest X-ray shows the outline and apparent size of your child’s heart, as well as the lungs and surrounding structures. It may help the team identify changes in the lungs or patterns that suggest increased or reduced blood flow through them. It does not provide the same detailed information about the heart’s chambers, valves or pumping function as an echocardiogram.
A chest X-ray uses ionising radiation and is not required for every child attending a cardiology appointment. It should only be recommended when the expected clinical information is likely to outweigh the small radiation risk.
Blood Tests and Genetic Testing
Blood tests are not required at every paediatric cardiology appointment, but they may be recommended when the cardiologist needs additional information about your child’s health. If an inherited heart condition is suspected, genetic or genomic testing may also be discussed as part of a specialist assessment.
Testing may identify a relevant genetic change, find no identifiable cause or detect a change whose significance is uncertain. Because the result may have implications for relatives, the inherited cardiac conditions or genetics team should explain what the test can and cannot show and whether specialist counselling or family testing may be appropriate.
A variant of uncertain significance is not a confirmed disease-causing gene change and cannot be used by itself to change clinical management or guide predictive testing in relatives. The genetics team will explain whether further investigation is appropriate and whether the result may need to be reviewed as scientific evidence develops.
Cardiac MRI
A cardiac MRI uses a strong magnetic field and radio waves to create detailed images of your child’s heart and major blood vessels. It can provide information about anatomy, pumping function, blood flow and, in selected cases, the heart muscle itself. Unlike an X-ray or CT scan, MRI does not use ionising radiation.
Your child will need to remain still, and the scanner can be noisy. Before the appointment, the team will complete a safety assessment covering implants, devices and possible metal objects. Some children may need contrast, sedation or a general anaesthetic, depending on their age and the type of images required. The team will explain the relevant preparation, benefits and risks.
Cardiac CT Scan
A cardiac CT scan uses X-rays and computer processing to create detailed images of your child’s heart and blood vessels. It may be recommended when the team needs a rapid or particularly detailed view of the heart or blood vessels, or when echocardiography or MRI is unsuitable or has not provided enough information.
Some children need an injection of contrast material, and younger children may require sedation or a general anaesthetic if they cannot remain still. CT uses ionising radiation, so the scan should be clinically justified and the imaging team will tailor the radiation exposure to your child’s size and the information required. The team should also explain any relevant contrast, allergy or kidney-function considerations.
Tilt-Table Testing
A tilt-table test is a specialist investigation that may be considered for selected children or young people with recurrent fainting, dizziness or symptoms related to standing when the initial assessment has not provided a clear explanation. It is not routinely required for every child who faints.
Your child lies securely on a special table that moves from a horizontal to a more upright position while their heart rate, ECG and blood pressure are monitored. The test may reproduce their usual symptoms. Follow the service’s preparation instructions carefully, but do not stop medicines or restrict food and drink unless the team has specifically told you to do so.
Cardiac Catheterisation and Angiography
Cardiac catheterisation is an invasive specialist procedure that can provide detailed information about pressures, oxygen levels, blood flow and anatomy within your child’s heart and blood vessels. It may be used to clarify a diagnosis, plan treatment or, in some cases, treat a heart problem during the same procedure.
A thin catheter is passed through a blood vessel, commonly from the groin, and guided towards the heart. Contrast and X-ray imaging may be used. Depending on your child’s age, health and the type of procedure, sedation or a general anaesthetic may be required. The team should explain the expected benefit, recovery and individual risks. These can include bleeding or bruising at the catheter site, reduced blood flow or injury to a blood vessel, infection, an abnormal heart rhythm, a contrast reaction and exposure to ionising radiation.
Specialist Electrical Tests
An electrophysiology study is an invasive test used to examine the heart’s electrical pathways in greater detail. It may be recommended when the cardiologist needs to identify the source of a significant abnormal rhythm or decide whether catheter ablation may be appropriate.
Thin electrode catheters are passed through blood vessels and guided to the heart. In some cases, an abnormal electrical pathway can be treated with ablation during the same procedure when this has been planned and consented to. The team will explain the anaesthesia, possible benefits, recovery and risks, including bleeding, infection, blood-vessel injury, abnormal rhythms and damage to the heart’s normal electrical system.
Myth vs Fact
| Myth | Fact |
| Every child referred to a paediatric cardiologist needs every available heart test. | Tests are selected according to your child’s symptoms, age, medical history, family history and examination findings. Many children need only a small number of first-line investigations. |
| An ECG sends electricity into your child’s body. | An ECG only detects and records the electrical signals naturally produced by the heart. It does not deliver electricity. |
| An echocardiogram exposes your child to radiation. | A standard echocardiogram uses ultrasound waves rather than X-rays and does not use ionising radiation. |
| A normal resting ECG rules out every heart-rhythm problem. | A resting ECG records only a short period. Symptoms that happen occasionally may require Holter monitoring, an event recorder or another longer-term monitor. |
| Cardiac MRI and cardiac CT use the same type of imaging. | MRI uses a magnetic field and radio waves and does not use ionising radiation. CT uses X-rays and therefore involves radiation exposure. |
Key Takeaways
- Your child’s tests will be selected according to their symptoms, age, examination findings, medical history and family history.
- An ECG assesses the heart’s electrical activity, while an echocardiogram provides information about its structure, movement and blood flow.
- Longer-term rhythm monitors may be needed when palpitations, fainting or dizziness do not occur during a short clinic ECG.
- Cardiac MRI does not use ionising radiation, whereas chest X-rays and CT scans do.
- Sedation, general anaesthesia and invasive investigations are only considered when they are expected to provide important clinical information or allow treatment.
- Do not fast your child or change their medicines unless the cardiology team has provided specific instructions.
- Call 999 if your child has severe breathing difficulty, suddenly develops blue or grey lips, tongue, face or skin, does not fully recover after fainting, or faints during exercise or while lying down.
Frequently Asked Questions (FAQs)
1. What are the most common tests used in paediatric cardiology?
Common paediatric cardiology tests include a resting ECG, an echocardiogram, pulse oximetry, blood pressure measurement and, when needed, portable heart-rhythm monitoring. These investigations may be carried out by different members of the cardiac team and are selected according to your child’s symptoms and clinical assessment.
2. Are paediatric heart tests painful?
Many first-line paediatric heart tests are non-invasive and generally painless. ECGs, echocardiograms, pulse oximetry and routine blood pressure measurements do not involve surgery, although electrodes, probe pressure or an inflating cuff may feel uncomfortable. Blood tests, implantable monitors, catheterisation and EP studies are invasive, and the team will explain the pain relief, sedation or anaesthesia used.
3. How does the cardiologist decide which heart tests my child needs?
The cardiologist selects tests based on your child’s age, symptoms, physical examination, medical history and family history. Initial tests may provide reassurance, suggest a diagnosis or show that further monitoring or imaging is required, but one normal test cannot necessarily rule out every heart condition.
4. What is the difference between an ECG and an echocardiogram?
An ECG records the heart’s electrical activity to assess heart rate and rhythm, while an echocardiogram uses ultrasound to create moving images of the heart’s structure, valves, pumping function and blood flow. These tests provide different but complementary information.
5. When is a Holter monitor recommended for a child?
A Holter monitor may be recommended when symptoms such as palpitations, dizziness or fainting occur often enough to be captured during a 24- to 72-hour recording. If episodes are less frequent, the cardiologist may recommend a longer-term event monitor or, in selected cases, an implantable loop recorder.
6. Will my child need sedation for heart tests?
Most children do not require sedation for routine heart tests. Sedation may occasionally be recommended for younger children who cannot stay still during longer imaging tests, such as a detailed echocardiogram or cardiac MRI.
7. Are MRI and CT scans safe for children?
Cardiac MRI and CT can both be used safely when they are clinically justified and appropriate precautions are followed. MRI does not use ionising radiation but requires safety screening and may involve contrast, sedation or a general anaesthetic. CT uses ionising radiation and may also require contrast, so the scan is adjusted to obtain the necessary information with the lowest appropriate exposure.
8. Can a normal ECG rule out all heart problems?
No. A resting ECG provides only a short recording of the heart’s electrical activity. It may not detect an intermittent rhythm problem, and it does not provide the same structural information as an echocardiogram. The cardiologist may recommend longer rhythm monitoring, imaging or another investigation depending on your child’s symptoms.
9. Does my child need to prepare for paediatric cardiology tests?
Preparation depends on the specific test. Most ECGs and echocardiograms require little or no preparation, while MRI scans, sedated procedures or cardiac catheterisation may involve fasting or other instructions. Always follow the guidance provided by your hospital or clinic.
10. Will my child receive test results on the same day?
Some ECG and echocardiogram findings may be discussed during the appointment, depending on the service and whether further review is required. Holter recordings, MRI, CT, genetic testing and specialist procedures usually need additional analysis, and the team should explain when and how you will receive the results.
Final Thoughts: Understanding Your Child’s Paediatric Heart Tests
Learning that your child needs heart tests can naturally feel worrying. Many first-line investigations, including ECGs, echocardiograms and external ambulatory rhythm monitoring, are non-invasive. More specialised tests are recommended only when they may provide important additional information or allow treatment.
The cardiologist will explain why each test has been suggested, what preparation is needed and when you can expect the results. If your child has been referred for a cardiac assessment, you can contact London Paediatric Clinic to arrange a consultation with a paediatric cardiologist in London and discuss the most appropriate next steps.
References:
- NHS (2023) Electrocardiogram (ECG). Available at: https://www.nhs.uk/tests-and-treatments/electrocardiogram/
- NHS (2026) Echocardiogram. Available at: https://www.nhs.uk/tests-and-treatments/echocardiogram/
- University Hospital Southampton NHS Foundation Trust (no date) ‘Diagnosis and treatment (children’s cardiac)’. Available at: https://www.uhs.nhs.uk/for-visitors/southampton-childrens-hospital/childrens-services/childrens-cardiac/diagnosis-and-treatment
- Great Ormond Street Hospital for Children NHS Foundation Trust (no date) Tests we may perform in the Electrophysiology Service. Available at: https://www.gosh.nhs.uk/wards-and-departments/departments/clinical-specialties/electrophysiology-serviceheart-rhythm-disorders/tests-we-may-perform/
- Flynn, J.T. et al. (2022) ‘Ambulatory Blood Pressure Monitoring in Children and Adolescents: 2022 Update: A Scientific Statement From the American Heart Association’, Hypertension, 79(7), pp. e114–e124. Available at: https://pubmed.ncbi.nlm.nih.gov/35603599/
- NHS (2026) X-ray. Available at: https://www.nhs.uk/tests-and-treatments/x-ray/
- NHS (2025) MRI scan. Available at: https://www.nhs.uk/tests-and-treatments/mri-scan/
- NHS (2023) CT scan. Available at: https://www.nhs.uk/tests-and-treatments/ct-scan/
- Kingston and Richmond NHS Foundation Trust (2025) ‘MRI with sedation (children)’. Available at: https://www.kingstonandrichmond.nhs.uk/patients-and-families/patient-leaflets/mri-with-sedation
- Norfolk and Norwich University Hospitals NHS Foundation Trust (2023) ‘Cardiology Advice and Referral Pathways – Paediatrics’, CA4073 v7. Available at: https://www.nnuh.nhs.uk/publication/download/cardiology-advice-and-referral-pathways-paediatrics-ca4073-v7/
- Steinberg, J.S. et al. (2017) ‘2017 ISHNE-HRS expert consensus statement on ambulatory ECG and external cardiac monitoring/telemetry’, Annals of Noninvasive Electrocardiology, 22(3), e12447. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6931745/
- NHS (2023) ‘Fainting’. Available at: https://www.nhs.uk/symptoms/fainting/
- NHS (2023) ‘Blue or grey skin or lips (cyanosis)’. Available at: https://www.nhs.uk/symptoms/blue-skin-or-lips-cyanosis/
- Great Ormond Street Hospital for Children NHS Foundation Trust (2020) ‘Electrophysiology (EP) study’. Available at: https://www.gosh.nhs.uk/conditions-and-treatments/procedures-and-treatments/electrophysiology-ep-study/
- Royal Devon University Healthcare NHS Foundation Trust (2025) ‘Children’s exercise tolerance test’. Available at: https://www.royaldevon.nhs.uk/media/oqfhxskb/children-s-exercise-tolerance-test-rd-e-21-057-002.pdf
- Kingston and Richmond NHS Foundation Trust (2024) ‘Syncope (fainting) in children and young people’. Available at: https://www.kingstonandrichmond.nhs.uk/patients-and-families/patient-leaflets/syncope-fainting-children-and-young-people
- Great Ormond Street Hospital for Children NHS Foundation Trust (no date) ‘Living with an implantable loop recorder’. Available at: https://www.gosh.nhs.uk/wards-and-departments/departments/clinical-specialties/electrophysiology-serviceheart-rhythm-disorders/electrophysiology-procedures/living-with-an-implantable-loop-recorder/
- NHS England Genomics Education Programme (no date) ‘Variant of uncertain significance’. Available at: https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/variant-of-uncertain-significance-vus/
- University Hospital Southampton NHS Foundation Trust (no date) ‘Tilt table test for children’. Available at: https://www.uhs.nhs.uk/Media/UHS-website-2019/Patientinformation/Childhealth/Tilt-table-test-for-children-644-PIL.pdf
- Leeds Teaching Hospitals NHS Trust (2026) ‘Your congenital cardiac catheter’. Available at: https://www.leedsth.nhs.uk/patients/resources/your-congenital-cardiac-catheter/
- Great Ormond Street Hospital for Children NHS Foundation Trust (no date) ‘Arrhythmias’. Available at: https://www.gosh.nhs.uk/conditions-and-treatments/conditions-we-treat/arrhythmias/