ECG

Electrocardiogram

An electrocardiogram - or ECG - is a simple and useful test which records the rhythm and electrical activity of your heart.

What happens in an ECG test?

Small sticky patches called electrodes are put on your arms, legs and chest. These are connected by wires to an ECG recording machine which picks up the electrical signals that make your heart beat. This electrical activity is recorded and printed onto paper.

How long will it take?

The whole test takes about five minutes and is completely painless. You will need to lie still though because moving can affect the results.

Watch the film below to see Manzoor's experience of an ECG test:

What can an ECG show?

An ECG can help detect problems with your heart rate or heart rhythm – called arrhythmias. It can help doctors tell if you’re having a heart attack or if you’ve had a heart attack in the past. Sometimes an ECG can indicate if your heart is enlarged or thickened.

An ECG is usually one of the first heart tests you will have. It does have some limitations, so often you will have one or more other tests too. An abnormal ECG reading doesn’t always mean there is something wrong with your heart.

Different types of ECG test

Exercise ECG or stress test

This is an ECG that is recorded while you are walking on a treadmill or cycling on an exercise bike. The aim of this test is to see how your heart works when you are more active. 

Find out more about what the exercise stress test involves

24-hour ECG recording

Also called Holter monitoring or ambulatory ECG monitoringhis involves continuously recording your heart’s electrical activity for 24 to 48 hours. This can help diagnose symptoms - such as palpitations - which don’t happen all the time.

What happens during the test?

  • You’ll have electrodes put on your chest and the wires attached to these will be taped down.
  • You’ll wear a small portable recorder on a belt around your waist which the wires will lead to.
  • While you’re wearing the ECG recorder, you can do everything you would normally do - except have a bath or shower.
  • It's safe and completely painless.
  • When the test is finished, you’ll return the recorder to the hospital so the results can be analysed by your doctor.

Cardiac event recorders

If you have symptoms that don’t happen frequently, your doctor might suggest using a cardiac event recorder. This can record the heart's activity for a longer period of time, or whenever symptoms occur.

There are different types of event recorders:

  • A portable cardiac event recorder is a small device which you hold to your chest when you experience symptoms.
  • An implantable loop recorder (ILR) is implanted under the skin on your chest in a surgical procedure under local anaesthetic. An ILR can continuously monitor your heartbeat for up to 14 months and help find out what may be causing your symptoms - such as dizzy spells or blackouts.

Want to know more?

For more information, you can:

  • watch our films about heart tests
  • talk to someone by calling our Heart Helpline on 0300 330 3311
  • order or download our resources below.
Tests for heart conditions booklet The road ahead - your guide to heart tests and treatments DVD Electrocardiogram - your quick guide
 Tests booklet  DVD - The road ahead  Electrocardiogram - your quick guide