Health Library

Electrocardiogram

(ECG; EKG)

by Amy Scholten, MPH

Definition

An electrocardiogram (ECG or EKG) measures the electrical activity of your heart. The heart generates an electrical signal, which flows out from your heart through your body. Small electrical sensors, called electrodes, are put on your skin to sense the electricity that began in your heart. The electrical activity is then turned into a graph. This can give doctors an idea of whether your heart is beating normally.

ECG/EKG Waves

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Reasons for Test

An ECG is used to:

  • Diagnose heart attacks and rhythm problems
  • Offer clues about other heart conditions and conditions not primarily related to the heart
  • Detect conditions that alter the body’s balance of electrolytes, such as potassium and magnesium
  • Detect other problems, such as overdoses of certain drugs

Symptoms that may prompt an ECG include:

  • Chest discomfort or pain
  • Shortness of breath
  • Palpitations
  • Anxiety
  • Weakness
  • Nausea or the feeling that you have to vomit
  • History of fainting

An ECG may also be obtained if you:

  • Are about to have surgery with general anesthesia
  • Are in occupations that stress the heart or where public safety is a concern
  • Are an older adult or have diabetes
  • Already have heart disease
  • Have had a heart-related procedure, such as getting a pacemaker

Possible Complications     TOP

There are no major complications associated with this test.

What to Expect    TOP

Prior to Test

You may:

  • Have a physical exam
  • Be asked about your medical history
  • Have your chest shaved if needed

Description of Test

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

After Test

You may resume activities as recommended by your doctor.

How Long Will It Take?

3-4 minutes

Will It Hurt?

No

Results

Your doctor will interpret the ECG. Based on the results and your other health information, you may need more tests or a treatment plan.

Call Your Doctor    TOP

Call your doctor if you have heart-related symptoms, such as chest pain or trouble breathing.

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

RESOURCES:

American Heart Association
http://www.heart.org
Heart Rhythm Society
http://www.hrsonline.org

CANADIAN RESOURCES:

Canadian Cardiovascular Society
http://www.ccs.ca
Heart and Stroke Foundation of Canada
http://www.heartandstroke.ca

References:

Electrocardiogram (EKG or ECG). American Heart Association website. Available at: http://www.heart.o.... Updated November 26, 2012. Accessed May 20, 2013.
Noninvasive tests and procedures. American Heart Association website. Available at: http://www.heart.o.... Updated April 15, 2013. Accessed May 20, 2013.
What is an electrocardiogram? National Heart, Lung, and Blood Institute website. Available at: http://www.nhlbi.nih.gov/health/health-topics/topics/ekg/. Updated October 1, 2010. Accessed May 20, 2013.
Last reviewed May 2013 by Michael J. Fucci, DO; Brian Randall, MD
Last Updated: 5/20/2013

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