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what is an EKG or ECG test and information on abnormal EKG readings

Electrocardiogram (EKG) tests are painless, non-invasive procedures used to monitor heart beats and rhythm.


Some of the first questions to ask when learning about EKGs, is what is an EKG and what does EKG stand for? An EKG, also known as an ECG, stands for electrocardiogram. The EKG is a medical test that records the electrical activity in your heart.1 A more detailed EKG definition is that it interprets the heart’s electrical impulses in order to diagnose heart conditions.2

Your heart emits tiny impulses of electricity which move throughout the heart muscle, making it contract. These impulses are detected and measured by EKG machines.2 The purpose of an EKG scan is to determine how fast your heart is beating and to detect any irregular heartbeats.1

Your doctor may schedule you for EKG testing to diagnose any heart problems or disorders. If you’ve been experiencing any abnormal heart symptoms, such as chest pain, breathing problems, or heart flutters, an EKG can be helpful in making a diagnosis.1 Your doctor may also send you for an EKG to check on your heart function if you have any other medical conditions, such as diabetes, high blood pressure, or if there is a history of heart disease in your family.2

Preparing for an Electrocardiogram

Once you’ve been scheduled for an EKG heart test there are a few things you should do to prepare:

  • Give your doctor a list of all medications and supplements.3 This includes common dietary supplements such as vitamin c or Ayurveda remedies.
  • Avoid drinking cold water or exercising before the test as this may record false test results.4
  • No fasting is required before the test.3
Patients should also notify their doctor if they currently have a pacemaker.2

Be sure to ask your doctor for details about the test and what to expect.

The next question to ask is how much is an EKG and is it covered by your medical insurance? If you live in the United States, there are two conditions where an EKG is covered. Medicare will cover one EKG scan if you’re referred by your doctor. As well, if the EKG is being used as a diagnostic test to determine your medical condition, it will also be covered.5 If you’re not covered by Medicare you can schedule a test with a private insurance company. For example, the cost quoted from Blue Cross Blue Shield is $40.00 to $100.00.6

In Canada, EKG testing is covered by your provincial MSP (Medical Services Plan) when requested by your doctor.7 If you wish to have an EKG test done privately, the cost may range anywhere from $900.00 to $1400.00.

What Happens During an EKG Test

For those wondering, ‘how does an EKG work?’ patients lie on their back for the entire test. The process is harmless and non-invasive. The technician will place electrodes directly onto the skin on your arms, chest, and legs. These electrodes are soft patches and will stick to your skin. If necessary, your skin will be shaved so the patches adhere correctly.1,2,4

Up to 12 electrodes are used so that electrical activity can be recorded in different areas of your body. The electrodes are connected to the EKG machine which will read your heart’s electrical impulses and show the results on a monitor screen or on graph paper.1 There are three different types of electrocardiograms.

1. Standard EKG
The standard EKG, as outlined above, is done while you’re resting and in the hospital or doctor’s office. This EKG will only show heart abnormalities and irregularities if they happen during the test. It is typically used for heart problems that you’re experiencing all the time.1

2. Stress Test
The stress test is done when heart problems, such as an irregular heartbeat, only occur when the heart is beating fast. This may happen when exercising or under stress. To see the effects of a hard-working heart, the EKG scan will be performed while your heart is beating fast.1 Once the technician has applied the electrodes, you’ll be asked to exercise so the EKG can measure the effects.4

3. Portable EKG
If abnormal heart symptoms are intermittent and not constant, your doctor may have you wear a portable Holter or event monitor for 24 to 48 hours. This device will record the electrical impulses in your heart throughout a normal day.1

For those wondering ‘what does EKG measure?’ EKG testing is used to detect and diagnose heart problems. It can measure the following:1,2

  • Abnormal electrical impulses
  • Heat rate and rhythm
  • Thickness of the heart muscle
  • Evidence of damage to the heart
  • Evidence of compromised blood flow to the heart

How Long Does an EKG Take

On average, the standard EKG will take about 10 minutes to complete. If a Holter or event monitor is used, the portable device will be attached to you for 24 to 48 hours to ensure that intermittent heart irregularities are measured during that time period.1

You may get your test results immediately after the EKG is completed or you may have to wait up to a week, depending on when your own doctor has the results to go over with you.

EKG Interpretation

The results of your electrocardiogram will be measured and read by a trained technician using EKG calipers.9 Calipers are a digital tool used to take manual measurements of a EKG test.10 EKG strips from the cardiac monitor used during your EKG test will provide the technician with information about your results.8

After your EKG test, you’ll want to know what does an EKG show. An electrocardiogram will show how strong the electrical impulses are as they move through each section of the heart. It will also indicate whether EKG rhythms are steady and normal or if there is an irregular rhythm.1

Normal EKG

Normal heart rate will measure between 60 to 100 beats per minute.4

Normal EKG results will show a heart rhythm that is even and steady.4 If you have been experiencing abnormal heart symptoms and the EKG results are normal, you may require further testing and evaluation as a normal EKG doesn’t always rule out heart disease. Your doctor may schedule an electrocardiogram stress test to see how your heart reacts when it’s beating faster or may provide you with a Holter monitor to record heart activity over an extended period of time.1

Abnormal EKG

Abnormal EKG test results can mean several things. There may be an abnormality in the heart rhythm that doesn’t need medical attention as it has no effect on your health. An abnormal reading can also indicate a serious medical condition that needs immediate attention. Your doctor will be able to interpret the results of the EKG to determine the next steps. Abnormal EKG readings can be an indicator of several conditions:1

  • Abnormal heart rhythm
  • Lack of blood supply to the heart
  • Birth defects located in the heart
  • Enlargement of the heart
  • Inflammation of the heart muscle

The above information about EKG testing provides you with guidelines about what to expect when having an electrocardiogram.

Electrocardiogram EKG test infographic including information on how long does an EKG take and how to prep for the EKG machine

Ever wondered how to prepare for an Electrocardiogram (EKG) test? Use our guide to EKG tests to learn what does EKG measure and how long does an EKG test take.

Scientific Research Referenced in this Article

  1. U.S. National Library of Medicine: PubMed Health. (2014, June 11). Electrocardiogram. Retrieved October 24, 2017 from https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0062962/
  2. Joshi, A. & Tamar, A. (2014) A Review Paper on Analysis of Electrocardiograph (ECG) Signal for the Detection of Arrhythmia Abnormalities. International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering. Retrieved on October 24, 2017 from – View Reference
  3. John Hopkins Medicine. (n.d.). Electrocardiogram. Retrieved October 24, 2017 from – View Reference
  4. U.S. National Library of Medicine: Medline Plus. (2016, May 5). Electrocardiogram. Retrieved October 24, 2017 from https://medlineplus.gov/ency/article/003868.htm
  5. U.S. Centers for Medicare & Medicaid Services. (n.d.). EKG (electrocardiogram) screening. Retrieved October 24, 2017 from – View Reference
  6. Blue Cross and Blue Shield. Typical Costs for Common Medical Services. Retrieved October 24, 2017 from https://www.bluecrossma.com/blue-iq/pdfs/TypicalCosts_89717_042709.pdf
  7. Government of British Columbia. Services Covered by MSP. Retrieved October 24, 2017 from https://www2.gov.bc.ca/gov/content/health/health-drug-coverage/msp/bc-residents/benefits/services-covered-by-msp
  8. Pallavi, P. & Vaishali, V. (2004) Issues in QT interval measurement. Indian Pacing Electrophysial J. 4(4): 156-161. Retrieved on October 24, 2017 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1502066/
  9. Burke, GM. & Wang, N. (2014) S Assessment of reproducibility–automated and digital caliper ECG measurement in the Framingham Heart Study. Journal of Electrocardiology, 47(3): 288-293. doi: 1016/j.jelectrocard.2014.01.004
  10. Mehta, DD. & Nazir, NT. (2015) Single-lead portable ECG devices: Perceptions and clinical accuracy compared to conventional cardiac monitoring. J Electrocadiol, 48(4): 710-6. Retrieved on October 24, 2017 from https://www.ncbi.nlm.nih.gov/pubmed/25968916