Heart test
ECG (Electrocardiogram)
An ECG is a quick, painless test that records the heart's electrical activity through stickers on the skin. It checks heart rhythm and can show signs of a heart attack or other heart problems.
Quick answer
ECG (Electrocardiogram): what it is and what the results mean
An electrocardiogram (ECG) records the electrical signals that make the heart beat, producing a tracing of the heart's rhythm and activity.
- Why it is done: It is used to check for abnormal heart rhythms, investigate symptoms like chest pain, palpitations or breathlessness, detect signs of a heart attack, and monitor heart conditions.
- Understanding results: A doctor interprets the tracing, which can reveal rhythm problems, evidence of a current or past heart attack, and other clues.
What it is
An electrocardiogram (ECG) records the electrical signals that make the heart beat, producing a tracing of the heart's rhythm and activity.
Why it is done
It is used to check for abnormal heart rhythms, investigate symptoms like chest pain, palpitations or breathlessness, detect signs of a heart attack, and monitor heart conditions.
What to expect
Small sticky electrodes are placed on the chest, arms and legs and connected to a machine that records for a few seconds. It is completely painless and quick. Variations include a 24-hour monitor or an exercise (treadmill) ECG.
Understanding the results
A doctor interprets the tracing, which can reveal rhythm problems, evidence of a current or past heart attack, and other clues. It is often combined with other tests.
Good to know
Risks and limitations
An ECG is completely safe and painless — it only records, it does not put electricity into you. A normal ECG does not rule out all heart problems, so further tests are sometimes needed.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
ECG (Electrocardiogram): frequently asked questions
Does an ECG hurt?
No. An ECG is painless — sticky electrodes simply record the heart's natural electrical activity. Nothing is put into your body.
Can an ECG detect a heart attack?
An ECG can show signs of a heart attack happening or one that occurred in the past, which is why it is done urgently for chest pain — but it is used together with blood tests and assessment.
Related tests
Other heart test investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- Royal College of Radiologists / relevant professional body
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