An electrocardiogram (ECG) tests the electrical activity of the heart. It will appear as a pattern on a graph. It can help to show abnormal movements or working of the heart.

ECG Waves

nucleus image
Copyright © Nucleus Medical Media, Inc.

Reasons for Test

Some reasons this test may be done are to:

  • Look for the cause of chest pain, rapid heartbeat, and other symptoms that may be heart-related
  • Diagnose heart attacks and heart rhythm problems
  • Check a person's heart health before a surgery is done
  • Check a person's heart health after they have had a heart-related procedure, such as a pacemaker
  • Find out how well heart medicines are working

Possible Complications

There are no major problems linked to this test.

What to Expect

Prior to Test

The care team may meet with you to talk about:

  • Any allergies you may have
  • Current medicines, herbs, and supplements that you take
  • The need to stop smoking right before the test

Description of Test

You will be asked to lie quietly on your back. Six small, sticky pads will be placed across the chest. Other pads will be placed on the arms and legs. Wires will be attached to the pads. The wires will also connect to the ECG machine. You will not feel anything during the test.

How Long Will It Take?

5 to 10 minutes

Will It Hurt?

You will not have any problems after this test.


Your doctor will review the ECG. The results may lead to:

  • Diagnosis
  • More tests to confirm a diagnosis
  • A treatment plan

Call Your Doctor

Call your doctor if you have heart-related symptoms. This includes chest pain or problems breathing.

If you think you have an emergency, call for medical help right away.


American Heart Association
Heart Rhythm Society


Canadian Cardiovascular Society
Heart and Stroke Foundation of Canada


Electrocardiogram. National Heart, Lung, and Blood Institute website. Available at:
...(Click grey area to select URL)
Accessed September 22, 2020.
Electrocardiogram (ECG)—12-lead and in-hospital ECG monitoring. EBSCO DynaMed website. Available at: https://www.dyname.... Accessed September 22, 2020.
Electrocardiogram (EKG or ECG). American Heart Association website. Available at:
...(Click grey area to select URL)
Accessed September 22, 2020.
Noninvasive tests and procedures. American Heart Association website. Available at:
...(Click grey area to select URL)
Accessed September 22, 2020.
Last reviewed March 2020 by EBSCO Medical Review Board Kari Kassir, MD
Last Updated: 9/22/2020

EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

To send comments or feedback to our Editorial Team regarding the content please email us at healthlibrarysupport@ebsco.com. Our Health Library Support team will respond to your email request within 2 business days.