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What is an Electrocardiogram (ECG/EKG)?

May 1, 2024 • read

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What is an Electrocardiogram (ECG/EKG)?

The Electrocardiogram (ECG or EKG) is a quick, safe, and painless test that records the electrical activity in your heart. Each heartbeat starts with an electrical signal telling the heart muscle to contract, pumping the blood from your heart to where it needs to go. An ECG can help detect if your heart is pumping properly or not. 

What is an ECG? 

An ECG is more commonly known as the sticker test. Small sticky tabs about the size of a thumbnail are placed across your chest, arms, and lower legs, and these tabs contain electrodes that are connected to the ECG monitor via wires. 

The ECG machine measures and records the electrical activity through the heart showing the speed and rhythm of your heartbeats. It can detect abnormal heart rates, rhythms, injuries to the heart, and the effects of certain medications or devices like a pacemaker. The ECG’s recordings are seen on a screen or printed on paper as needed. 

This quick and non-invasive test can assist in diagnosing some heart conditions like coronary artery disease (heart attacks or angina), or abnormal heart rhythms like atrial fibrillation. A healthcare provider may recommend an ECG in preparation for an upcoming surgery or to investigate symptoms like lightheadedness, chest pains, or tightness for example. 

When would I need an ECG? 

An ECG is used to investigate symptoms that may be caused by a heart abnormality. Some symptoms that may lead to an ECG include: 

  • Chest pains, heaviness, or tightness 
  • Shortness of breath
  • Lightheadedness or dizziness
  • Fluttering, pounding, or skipping heartbeats (known as palpitations)
  • Racing heartbeats 
  • Fatigue or weakness
  • New exercise intolerance 

Your healthcare provider may order an ECG to monitor your recovery from a heart attack, or to detect abnormal heart rhythms (arrhythmias), blocked coronary arteries, enlargement of the heart muscle, or inflammation of the tissue surrounding the heart (pericarditis). Preventatively, ECGs can be ordered: 

  • In preparation for a scheduled surgery to rule out unknown heart disease 
  • If you have had heart problems in the past 
  • To see how well certain heart medicines or implanted pacemakers are working
  • If you are taking medicines that may affect the heart’s electrical activity like certain antidepressants or antibiotics 
  • If you have a strong family history of heart disease 

How you can prepare for an ECG

There is no special preparation for having an ECG done. There is no need to restrict what you eat or drink before an ECG, however on the day of the test is is best if you can: 

  1. Wear loose-fitted clothing to allow shirts and pant legs to be easily moved out of the way.
  2. Avoid wearing pantyhose, tights, or leggings that cannot be moved up. 
  3. Avoid applying lotions, creams, talcums, moisturizers, or perfumes on the day of the test.
  4. Avoid smoking and exercising just before the test. 

What you can expect when having an ECG

The ECG test itself is quick, usually taking about 5-15 minutes to complete. Having the recording interpreted by a cardiologist can take a few days. 

On the testing day, you will be asked to: 

  1. Remove any jewellery and clothing from your waist up and cover yourself with a privacy sheet or gown provided. 
  2. Pull up the bottom of your pants to expose your legs below the knees. 
  3. Lay on your back on the ECG bed. 
  4. Avoid moving and talking during the test as much as possible. Movement can interfere with the recordings.
  5. Ask any questions you may have about the ECG test.

If your arms, chest, or lower legs are very hairy, the technician may shave or trim small areas to allow the electrodes to stick to your skin better. A technician will: 

  1. Rub alcohol where the sticky tabs will be placed (across your chest, upper arms, and lower legs). 
  2. Apply the sticky sensors (usually 12-15 of them). During this process, the technician may feel for the spaces between your ribs or be required to lift breast tissue out of the way with your assistance or using the back of their hand. 
  3. Attach the sensors to the connection wires and to the ECG monitor.
  4. Remain in the room with you for the duration of the test (5-10 minutes). 
  5. Upon completion of the test, they will then remove the sticky electrodes and disconnect you from the machine. 

Understanding your ECG results – normal vs abnormal, understanding the graph readings 

Your ECG may only take a few minutes to complete, however, it could take a few days to have the recordings interpreted by a cardiologist. 

Factors that can interfere with your results include: 

  • Obesity 
  • Body shapes such as large barrel-sized chests
  • Exercise or smoking prior to the study 
  • Movement during the test 
  • Electrolyte imbalances 

It is important to know that the standard ECG takes a snapshot at the conduction in your heart. So it will capture something that is occurring continuously and may not detect things that may happen more sporadically. There are tests that monitor the activity in your heart over longer periods of time like a Holter monitor (explained below). 

What are the different types of ECGs? 

There are three types of tests that look at the electrical conduction in your heart using an ECG. A standard ECG, a stress test, and an ambulatory test. 

  1. Standard ECG is a quick, painless test that requires you to lay still for the duration of the test that takes about 5-10 minutes. 
  2. Stress tests can be done on a treadmill or with a medication that simulates the stress of exercise on your heart. Like in a standard ECG, you will be connected to a monitor with electrodes and recordings will be done before, during, and after exercise. During the test, the speed and incline will slowly increase. This test shows how well your heart can respond to different levels of exercise stress.
  3. Ambulatory ECGs are also known as Holter monitors. These are small compact devices that you would be sent home with and are to be worn over a period of days to weeks (72 hours or 14 days) as you carry on with your regular routine. This test is best used to detect irregular heart rates or rhythms that come and go and are difficult to detect on a standard ECG. It can help determine if symptoms like lightheadedness are related to abnormal electrical activity in your heart. 

Potential complications and side effects – rare side effects, when to get help 

ECGs are a safe, and non-invasive test. It does not send electric currents to the body. Some people may be sensitive to the electrode pad adhesives and can develop skin irritation or itchiness. If this were to happen, it’s often self-limiting and more likely when the electrodes are left for longer periods of time. 

An ECG is a quick and painless first test to look at how well your heart is functioning. Speak to a Canadian licensed physician or nurse practitioner today and see if you would benefit from an ECG. 

With more than 20 different kinds of medical providers available on Maple’s platform, virtual care is making it easy for plan members to connect with hard-to-reach specialists when needed. Maple can make treating conditions that are monitored with home devices or reviewing lab tests like ECGs more convenient with appointments anywhere and anytime that works for you. 

The information presented from Maple is not intended to replace the advice of your medical professional. Always consult with your medical professional with any health concerns specific to you. If you do not have a family doctor, or cannot get an appointment with your own as quickly as you like, Maple is here to help. Become a member and connect with a Canadian licensed physician today

Virtual care is not meant for medical emergencies. If you are experiencing an emergency like chest pain or difficulties breathing for example, please call 911 or go to your nearest Emergency Room.

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