Electrocardiogram (ECG)


An Electrocardiogram (abbreviated to ECG) is a device used to measure the electrical activity of the heart. This can be useful in identifying heart problems.

What is an Electrocardiogram?

The heart contracts due to tiny electrical impulses, spread throughout the heart muscle by the Sinoatrial (SA) node (the hearts own, natural pacemaker).

An electrocardiogram detects and records these impulses. ECG's are used when a heart or circulatory system condition are suspected. Often it is one of the first tests to be conducted when a patient complains of chest pains or palpitations. An ECG may also be performed as a routine test before an operation for example.

What Does an ECG Show?

Different conditions produce different abnormal patterns. Conditions which can be detected include:

  • Coronary Heart Disease / Angina
  • A heart attack. The scan can also indicate how long ago the attack was through the damage to the heart muscle and scar tissue present.
  • Coronary Artery Disease
  • An enlarged heart
  • Abnormal heart rhythms
  • The effectiveness of heart medications

What Happens During an ECG?

Adhesive electrodes are placed on the skin over the chest, arms and even the legs. Up to 12 electrodes can be used and the skin may need to be shaved first to make sure the electrodes stick properly.

The actual test takes only around a minute to perform once all of the electrodes are in place. The results are then printed out for the Doctor to review.

In most cases the ECG is performed at rest. In a few cases it may be performed when the patient is exercising on a treadmill or stationary cycle. This is done when coronary artery disease is suspected and is known as an exercise stress test.

Is It Safe?

Yes! At rest an ECG is completely safe and pain-free. An exercise stress test carries a slightly higher risk and the patient may suffer chest pain when exercising which should clear once they stop. A Doctor is always present alongside the ECG technicians and will stop the testing if there is significant chest pain or if the readings on the ECG change.

Read more on:

MRI Scans

MRI stands for Magnetic Resonance Imaging. MRI scans were introduced in the 1980's and are now used frequently in the diagnosis of soft tissue injuries and other medical conditions.


X-Rays were first discovered in 1895 by a Physicist named Roentgen. X-Rays are the same wave-like electromagnetic energy form as visible light rays, however X-Rays have a shorter wavelength which is...

CT Scan

A CT scan (or cat scan) is an abbreviation of Computerised Tomography. CT scans show cross sectional images of soft tissues (muscles, tendons, ligaments, cartilage etc) as well as bone and calcific...

Nerve Conduction Studies

Nerve conduction studies are often run at the same time as an EMG. They are used to test the speed (velocity) and size of the signal sent along a nerve.