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12-Lead Electrocardiogram (ECG)

Nurse With Cardiology Patient

12-Lead Electrocardiogram (ECG)

“ECG is the most common cardiac investigation. It provides a graphic representation of the electrical activity of the heart. This representation indicates the overall underlying rhythm of the heart and will indicate any arrhythmias or abnormalities in the conduction system of the heart.”


What is an Electrocardiogram (ECG)?

An ECG records the electrical activity of the heart. The heart produces tiny electrical impulses which spread through the heart muscle to make it contract. These impulses can be detected by the ECG machine. The machine amplifies the electrical impulses that occur at each heartbeat and records them on to a paper or computer.

You may need an ECG test if you have risk factors for heart disease such as high blood pressure, or symptoms such as palpitations or chest pain.  Or you may need it if you already have heart disease.

What does it involve?

 The specialist Physiologist will invite you into the ECG room, you will be asked to undress to the waist and put on a gown that should be left open at the front. If you require a chaperone, you may bring a friend or relative. Alternatively, the hospital may provide a chaperone at your request. You will be asked to lie on a couch and 10 stickers (electrodes) will be connected to your arms, legs and across the chest. Your details will then be entered onto the computer and a recording taken.

The electrocardiogram will take about 5 -10 minutes to complete.

How will I feel during the test?

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.)

Why is it being done?

 The electrocardiogram is commonly used to detect abnormal heart rhythms and to investigate the cause of chest pains.  The heart disorders that can be detected include abnormal heart rhythms, if the heart rate is very fast, slow or irregular, heart attacks (myocardial infarction) and enlarged hearts.


There are no risks associated with the test.


Are there any special precautions that I need to take before the electrocardiogram?

 No. You can take all your medication as normal, unless informed otherwise by your doctor. You can eat and drink as normal.


When will I get my results from the test?

We are unable to provide results of the test on the day of your appointment. All results will be sent to the referring doctor. You will need to arrange a follow up appointment with the doctor to discuss the results of the test(s).


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