An ECG – or
electrocardiogram - is a simple and useful test which records the
rhythm and electrical activity of
Small sticky patches called electrodes will be
put onto your arms, legs and chest. These are connected to an ECG
recording machine which picks up the electrical
signals that make your heart beat.
The test will only take a few minutes and is painless.
What can an ECG show?
An ECG can detect problems you may have with your heart rhythm. It can help doctors tell
if you are 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.
Types of ECGs
24-hour ECG recording
Your heart will be continuously recorded by an ECG for over 24
hours. Your doctor might also call it Holtor
monitoring or ambulatory ECG.
You’ll have electrodes put on your chest and the wires attached
to these will be taped down. These wires will lead to a small
portable tape recorder, which you’ll wear on a belt around your
A 24-hour ECG helps to diagnose symptoms, such as palpitations,
which only happen now and again. Sometimes it can show up an
abnormal heart rhythm that might need
treatment. It can also help reassure patients if the results are
Cardiac event recorders
If your symptoms are less frequent, 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 several different types of event recorders. Some are
portable and you hold them to your chest when you have a
Others devices are implanted under your skin. These are called
Implantable loop recorders (ILR). They can
continuously monitor you heartbeat for up to 14 months.
Your doctor might also refer to this as an exercise
stress test or an exercise tolerance
test. It’s an ECG that is recorded while you are walking
on a treadmill or cycling on an exercise bike. The idea of this
test is to see how your heart works when you are more active.
The test starts off at an easy rate, and is gradually made
harder, either by increasing the speed and slope of the treadmill
or by putting a brake on the bike. A doctor or technician will
carefully monitor your ECG at regular intervals throughout the
The test usually lasts from a few minutes up to 15 minutes.
Make sure you let staff know if you have any symptoms such as
chest pain or discomfort, or if you get very tired or short of
breath during the test.
How do I prepare for this test?
What can the test show?
- Wear light, comfortable clothes and shoes.
- Avoid having a heavy meal a few hours before the test.
- Sometimes your doctor may advise you to stop taking certain
heart medications for one or two days before the test.
Your heart needs more blood and oxygen when you are active, so
the exercise ECG can show whether your heart is getting enough
blood from the coronary arteries during physical activity. This can
help doctors find out if you have coronary
heart disease and, if so, how severe it is.
An exercise ECG is also helpful for looking at how well the
heart is working after angioplasty or