ECG
What is an ECG?
An ECG – or electrocardiogram - is a simple and useful test
which records the rhythm and electrical
activity of your heart.
What will happen during my ECG?
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 machine records a
few beats from each set of the electrodes onto paper. 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.
There are a few other types of ECG, including a 24-hour
ECG, cardiac event recorders and an
exercise ECG.
24-hour ECG recording
This means that your heart will be continuously recorded by an
ECG for over 24 hours – your doctor might also call it
Holtor monitoring or ambulatory
ECG.
What will happen during my 24-hour 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
waist.
What can a 24-hour ECG show?
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 normal.
Cardiac event recorders
If your symptoms are less frequent, your doctor might suggest
using a cardiac event recorder which can record the heart's
activity for a longer period of time or whenever symptoms occur.
There are several different types of event recorders. Some are
portable and you hold them to your chest when you have a symptom.
These are called patient-activated recorders.
There’s also a device called an implantable loop
recorder, which is implanted under your skin.
Exercise ECGs
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.
How do I prepare for this test?
- 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.
What will happen during my exercise ECG?
Electrodes will be put on your chest and you’ll be asked to walk
on a treadmill or cycle on an exercise bike. 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 break on the bike.
A doctor or technician will carefully monitor your ECG at regular
intervals throughout the test. 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. The
test usually lasts from a few minutes up to 15 minutes.
What can the test show?
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
bypass surgery.
More information
See our booklet Tests
for heart conditions.
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