An ECG (electrocardiogram) records the electrical activity of your heart, while an echocardiogram uses ultrasound to show the heart's structure and pumping. An ECG is usually the first test for palpitations, dizziness or a check-up, and an echocardiogram is used when a murmur, breathlessness or swelling suggests a problem with the heart muscle or valves. Many people need one, some need both, and a clinician can help you decide.
What is the difference between an ECG and an echocardiogram?
Think of your heart as a house. An ECG checks the wiring: the electrical signals that tell your heart when to beat. An echocardiogram checks the building itself: the walls, the rooms, the doors and how well everything moves.
Both tests are painless, use no radiation and are very safe. They simply answer different questions, which is why one is not a replacement for the other.
| Resting 12-lead ECG | Echocardiogram | |
|---|---|---|
| What it looks at | Heart rhythm and electrical signals | Heart chambers, muscle, valves and blood flow |
| How it works | Small sticky pads on your chest, arms and legs | Ultrasound probe moved over your chest with gel |
| How long it takes | About 5–10 minutes | Usually 30–45 minutes |
| Typical reasons | Palpitations, dizziness, check-ups, medicals | Murmurs, breathlessness, swollen ankles, known heart conditions |
| Price at The Heart Clinic | £95 | £365 |
What does an ECG check for?
A resting ECG takes a snapshot of your heart's electrical activity over a few seconds. It can help your clinician look for:
- Irregular or abnormal heart rhythms, such as atrial fibrillation
- A heart rate that is too fast or too slow
- Signs of strain on the heart, or changes that may suggest a previous heart attack
- Problems with how electrical signals travel through the heart (conduction problems)
Because it is quick and simple, an ECG is often the starting point. An ECG may also be requested as part of some licensing medicals; for example, Motorsport UK can require one for certain competition licences. If you need a TfL or other occupational medical, check whether the form or examining doctor asks for an ECG.
One limit to keep in mind: a resting ECG only records what is happening during those few minutes. If your symptoms come and go, a normal ECG does not always rule out a rhythm problem. In that case, a longer recording with a Holter monitor may be more useful.
What does an echocardiogram check for?
An echocardiogram (often called an "echo") is an ultrasound scan of the heart, similar to the scan used in pregnancy. It produces moving pictures that let a trained sonographer and cardiologist see how your heart is built and how well it works. It can help assess:
- The size of your heart chambers and the thickness of the heart muscle
- How strongly your heart pumps
- Whether your heart valves open and close properly, or are leaking or narrowed
- Fluid around the heart, and some heart problems present from birth
An echo does not give a detailed picture of your heart rhythm, which is why it is often paired with an ECG. For a fuller look at what the scan reveals, see our guide on what an echocardiogram shows.
Which heart test do I need for my symptoms?
This is only a general guide. Your GP or clinician will advise on what is right for you.
An ECG is often the first step if you have:
- Palpitations (a fluttering, pounding or skipping heartbeat)
- Dizziness or light-headedness
- A family history of heart rhythm problems
- A medical that asks for an ECG
An echocardiogram is often suggested if you have:
- A heart murmur heard by a doctor
- Breathlessness when doing everyday things, or when lying flat
- Swollen ankles or legs
- High blood pressure that has been present for some time
- A known valve or heart muscle condition that needs monitoring
- An abnormal ECG result that needs looking into further
If palpitations are your main concern, our article on palpitations and which heart test to choose goes into more detail.
Should I have both tests?
Often, yes. The two tests complement each other. An ECG might pick up a sign that the heart muscle is thickened, and an echo can then confirm whether that is the case. Equally, an echo might show an enlarged chamber, and an ECG can check whether this is affecting your rhythm.
Having both gives your clinician a more complete picture, which can be reassuring if you are worried or have symptoms that are hard to pin down.
When should I get urgent help instead?
Planned heart tests are not for emergencies. Call 999 if you have:
- Chest pain, pressure or tightness, especially if it spreads to your arm, jaw, neck or back
- Collapse, or fainting with chest pain or palpitations, or while exercising
- Severe breathlessness
If you have symptoms that worry you but are not an emergency, speak to your GP or call NHS 111. If you become breathless when lying down, ask for an urgent GP appointment rather than waiting for a planned test. The NHS also has helpful information on what to expect from an ECG.
Frequently asked questions
Is an echocardiogram better than an ECG?
Neither is better; they look at different things. An ECG checks your heart's rhythm and electrical signals, and an echocardiogram checks its structure and pumping.
Can an ECG detect heart valve problems?
An ECG cannot see the valves directly. It may show indirect signs of strain, but an echocardiogram is the test used to look at the valves themselves.
Can an echocardiogram detect an irregular heartbeat?
An echo may show that your heart is beating irregularly during the scan, but it is not designed to identify the type of rhythm problem. An ECG or Holter monitor is better for that.
Do I need to prepare for either test?
Very little preparation is needed. Wear a top that is easy to remove, and keep taking your usual medicines unless a doctor tells you otherwise.
Do I need a GP referral?
No. You can book yourself in at The Heart Clinic, and referrals from GPs and specialists are also welcome.
Can I have these tests at home?
Yes. Both an ECG and an echocardiogram can be done during a home visit in London, Hertfordshire or Buckinghamshire.
Booking an ECG or echocardiogram with The Heart Clinic
You can book a resting 12-lead ECG or an echocardiogram at our Luton clinic or as a home visit, with Consultant Cardiologist oversight and a written report usually within 24 working hours. Prices are all-inclusive and listed on our pricing page. If you are unsure which test suits you, get in touch by phone or WhatsApp on 07853 215671, Monday to Saturday, 9am–6pm.