An ECG (electrocardiogram) helps doctors find out how well your heart is working by recording the signals it sends out during each heartbeat. The heart produces tiny electrical impulses which spread through the heart muscle to make it beat. The ECG machine detects these signals and produces a printed record for your doctor to look at. An ECG test can be carried out during a single appointment, or your doctor may request that you are monitored over the course of a normal day's activities - this is called a 24 hour ambulatory ECG.
24 Hour Ambulatory ECG
Your doctor may advise you to have this test if he or she suspects that your heart is not beating properly all the time, a type of condition known as arrhythmia. You may be experiencing arrhythmias if you ever have palpitations or feel dizzy. Because arrhythmias come and go, they may not happen while the doctor is examining you. For this reason, your heart needs to be checked continually over a longer period of time. This test records the electrical activity of your heart when you are walking about (ambulatory) and doing your normal activities.
You do not need to make any special preparations for your ECG. If you are on any medication, please tell the reception staff when you arrive so that they can record it in your notes. Some medications may affect what your ECG looks like, and doctors need to be aware of this when they are analysing your ECG results. If you have any questions or need advice, please contact us on 0845 603 0854, and we will arrange for a clinician to ring you before your appointment.
If you need help because you speak a different language, or you would like a friend, relative or carer to come with you, please let us know when you book your appointment.
Please arrive 15 minutes before your appointment time; if you are late we may not be able to carry out your test. Please do not bring children with you to your appointment.
Single test ECG
When you arrive, our staff will explain the procedure to you and answer any questions you may have. We will clean your skin and attach up to 12 self-adhesive (sticky) pads to your arms, legs and chest. If your clothes are not loose enough, we may ask you to undress down to your underwear so that we can attach the pads easily. If you have a lot of hair on your skin, we may need to shave that area to make sure that the pads stay in close contact with your skin.
Once we have attached all the pads to your skin, we will connect them to the ECG machine using leads. The ECG machine detects the electrical impulses during each heartbeat and sends them to a computer.
The ECG machine analyses the recording and produces a printed record. A specialist will then look at the results and send a report back to the doctor who referred you. The test takes between 5 and 15 minutes to do. After the test, we will remove the pads.
24 Hour Ambulatory ECG
When you arrive, our staff will explain the procedure to you and answer any questions you may have. Small metal pads will be stuck on to your chest and connected by leads to a small lightweight recorder (often called a Holter monitor). The recorder is attached to a belt which you wear around your waist, a bit like wearing a personal stereo.
It takes about 10 minutes for us to fit the pads and recorder. You then go about your normal activities for up to the next 24 hours. You wear the recorder when you are asleep as well. You should not have a bath or shower as the recorder must not get wet.
We will give you a diary to record times when you develop any symptoms (such as palpitations). Your diary record can be compared with your ECG printout to see if you had an arrhythmia at the same time as the symptoms. A doctor may ask you to do some of the activities which you know have brought on symptoms in the past to try and produce the same reaction.
There are some variations in the equipment that we may use:
• On some recorders, you press a button whenever you experience symptoms. The time you pressed the button will show up on the printout.
• Some recorders only switch on if your heart rate is unusual.
You will need to return to the clinic as instructed by the technician to return the equipment. The machine then analyses the recording and produces a result. A specialist will look at the results and send them to the doctor who referred you.
The doctor who referred you will receive your ECG results. You should telephone to confirm that they have received your report before arranging an appointment, unless the doctor has made different arrangements with you.
Why am I having an ECG?
ECGs can help find the cause of symptoms such as palpitations or chest pain. ECGs are also sometimes performed as part of routine tests, for example, before you have an operation. Your doctor may advise you to have a 24 hour ECG if he or she suspects that your heart is not beating properly all the time, a type of condition known as arrhythmia.
Are there any side effects?
An ECG recording is painless and harmless. (The ECG machine records electrical impulses coming from your body - it does not put any electricity into your body.)