An electrocardiogram, more commonly referred to as an ECG, is a simple and quick test used to check the electrical activity of your heart. It’s one of the most common heart investigations offered both on the NHS and privately in the UK. If you've ever experienced chest pain, palpitations, dizziness, or shortness of breath, your doctor may have suggested an ECG to find out what’s going on.
I’ll explain exactly what an electrocardiogram is, what it can show, how it's done, and when you might need one. I'll also share what to expect during the test, and what happens afterwards.
What Is an Electrocardiogram?
An ECG records the electrical signals that trigger your heart to beat. Every time your heart beats, it sends an electrical impulse through your heart muscle. An electrocardiogram captures this activity using small sticky pads placed on your skin, usually across your chest, arms, and legs. These signals are then printed out or displayed on a screen as a graph, showing how your heart is functioning.
It’s painless, non-invasive, and takes just a few minutes. Most importantly, it helps detect irregularities that might not be obvious through symptoms alone.
What Can an ECG Detect?
An electrocardiogram can provide valuable information about your heart. It can help identify:
Irregular heart rhythms (arrhythmias)
Evidence of a previous heart attack
Ongoing or silent heart attacks
Heart rate abnormalities (too fast or too slow)
Problems with the heart's structure (such as enlarged chambers)
Issues with the heart’s electrical pathways
However, it’s worth noting that while an ECG is helpful, it’s just one part of a larger assessment. Sometimes, if results are unclear or borderline, you may need additional tests like an echocardiogram, exercise tolerance test, or 24-hour Holter monitor.
When Should You Have an ECG?
There are a few situations where your GP or a cardiologist might request an electrocardiogram:
You’re experiencing chest pain, fainting, or palpitations
You have a history of heart disease or stroke
A family member has been diagnosed with a heart condition
You’re starting a new medication that may affect the heart
You’re being assessed for surgery or another medical procedure
You’re applying for a DVLA medical test or professional driving licence
As part of a routine heart screening, especially if you're over 40 or have high blood pressure, diabetes or raised cholesterol
Even people without symptoms may benefit from a one-off ECG if they’re at higher risk due to age or family history.
How Is an ECG Carried Out?
The test is usually done in a GP surgery, hospital, or private cardiology clinic. Here’s what happens:
You’ll be asked to remove your top and lie down on an examination bed.
Small sticky electrodes will be placed on your chest, arms, and legs.
These electrodes are connected to the ECG machine via soft wires.
You’ll be asked to lie still and breathe normally during the test.
The machine will record your heart’s electrical signals for around 10 seconds.
The results will either be printed out or saved digitally.
There’s no need to fast beforehand, and the test usually takes around 5–10 minutes from start to finish.
Are There Different Types of ECGs?
Yes, there are several types depending on your symptoms and how often they occur:
Type of ECG | When It’s Used |
Resting ECG | The most common test, done while you're lying still |
Ambulatory (24–48hr) ECG | Worn over 1–2 days to catch irregular rhythms that come and go |
Exercise ECG (ETT) | Done while walking on a treadmill to see how the heart responds to activity |
Event Recorder | A small monitor used over weeks for very occasional symptoms |
If your symptoms happen regularly and predictably, a resting ECG may be enough. But if they’re infrequent, your cardiologist might recommend one of the longer-term options to increase the chance of catching an abnormal rhythm.
Is an ECG Safe?
Absolutely. An electrocardiogram is entirely safe and painless. It does not involve any needles, radiation, or injections. The electrodes simply monitor what your heart is already doing they don’t send any signals into your body.
You might feel a bit cold from the gel or slightly uncomfortable when removing the stickers, but that’s all.
Can an ECG Be Wrong?
Like all tests, an ECG has its limitations. It only captures your heart’s electrical activity during a brief moment in time. If you’re not experiencing symptoms at that exact time, the test might appear normal. That doesn’t mean there’s no issue it just means further investigation could be needed. For that reason, your doctor will always interpret your ECG alongside your symptoms and medical history.
ECG on the NHS vs Private, so What is the Difference?
Both the NHS and private clinics offer ECG testing, but the experience can be different depending on availability and urgency:
NHS ECGs are free but may involve longer wait times, especially for non-urgent cases.
Private ECGs are usually available same-week and cost between £80–£150.
Some private cardiology clinics, like us we offer ECGs as part of a broader cardiac screening package, which may also include an echocardiogram and consultation.
If you’re having symptoms or need a quick turnaround (e.g. for travel, work, or DVLA testing), private testing can be more convenient.
Do I Need to Prepare?
There’s no special preparation needed for a standard ECG:
Wear a loose-fitting top that’s easy to remove
Avoid oily or greasy skin creams that may affect the electrodes
If you’re wearing tights or long socks, you might be asked to roll them down
If you’re having a stress ECG, your clinic may advise avoiding caffeine and eating a light meal beforehand.
What Happens After the ECG?
Once your ECG is done:
If your GP ordered the test, they’ll usually receive the results within a few days.
If it was done in a private setting, the results may be reviewed immediately by a cardiologist.
If something abnormal is detected, you may be referred for further testing (e.g. echocardiogram, CT coronary angiogram, or blood tests).
In some cases, treatment can begin straight away. For example, if an arrhythmia is discovered, your doctor might start medication or refer you to a heart rhythm specialist.
Summary
An electrocardiogram is one of the quickest, safest, and most useful ways to investigate heart symptoms. It’s painless, affordable, and widely available across the UK. Whether you’re having chest pain, palpitations, or just want reassurance due to a family history of heart disease, an ECG can provide valuable insights into your heart’s health.
At Heartsure, we regularly carry out ECGs as part of our wider cardiology service. We’re always happy to explain what your results mean and guide you through the next steps if further testing is needed.
