An electrocardiogram - or ECG - is a simple and
useful test which records the rhythm and electrical activity of
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
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 monitoring)
This 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
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
There are different types of event
- 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.
Where can I find out more?
Order or download our booklet
Tests for heart conditions or watch our films about heart tests. If
you'd like to talk to someone, call our
Heart Helpline on 0300 330 3311.