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Electrocardiogram (ECG)

An electrocardiogram (ECG) is a test that measures the electrical activity in the heart.

Why an ECG is done

An ECG is done to check for any problems with a person’s heart. An ECG may be done to:

  • assess any effects of medications or chemotherapies that are known to affect the heart
  • determine a baseline before chemotherapy starts
    • This baseline can be used throughout treatment to monitor the heart.
  • help decide whether a person is healthy enough to tolerate certain treatments

An ECG tests:

  • how fast the heart is beating
  • if the electrical conduction through the heart is normal
  • size and position of the heart chambers
  • any damage to the heart

How an ECG is done

The test may be done in a hospital, medical clinic or doctor’s office. It usually takes 5–10 minutes.

  • The person lies on a bed or examination table.
  • The person will remove clothes from the waist  up.
  • Special stickers called electrodes are placed on the skin of the arms, legs and chest. They may feel cold at first.
    • It may be necessary to shave or clip any hair so that they stick.
  • The ECG machine takes the information and makes it into a line drawing on paper called an electrocardiograph.

Special considerations for children

Being prepared for a test or procedure can reduce anxiety, increase cooperation and help the child develop coping skills. Parents and caregivers can help prepare children by explaining to them what will happen, including what they will see, feel and hear during the test.

  • Having an ECG does not hurt.
  • The child does not have to worry about electric shock because no electricity is passed from the ECG machine.

The preparation you can provide for an ECG depends on the age and experience of the child. See the following for more age-specific information on helping children cope with tests and treatment.


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