Doctors & patients are saying about 'A-Fib.com'...


"A-Fib.com is a great web site for patients, that is unequaled by anything else out there."

Dr. Douglas L. Packer, MD, FHRS, Mayo Clinic, Rochester, MN

"Jill and I put you and your work in our prayers every night. What you do to help people through this [A-Fib] process is really incredible."

Jill and Steve Douglas, East Troy, WI 

“I really appreciate all the information on your website as it allows me to be a better informed patient and to know what questions to ask my EP. 

Faye Spencer, Boise, ID, April 2017

“I think your site has helped a lot of patients.”

Dr. Hugh G. Calkins, MD  Johns Hopkins,
Baltimore, MD


Doctors & patients are saying about 'Beat Your A-Fib'...


"If I had [your book] 10 years ago, it would have saved me 8 years of hell.”

Roy Salmon, Patient, A-Fib Free,
Adelaide, Australia

"This book is incredibly complete and easy-to-understand for anybody. I certainly recommend it for patients who want to know more about atrial fibrillation than what they will learn from doctors...."

Pierre Jaïs, M.D. Professor of Cardiology, Haut-Lévêque Hospital, Bordeaux, France

"Dear Steve, I saw a patient this morning with your book [in hand] and highlights throughout. She loves it and finds it very useful to help her in dealing with atrial fibrillation."

Dr. Wilber Su,
Cavanaugh Heart Center, 
Phoenix, AZ

"...masterful. You managed to combine an encyclopedic compilation of information with the simplicity of presentation that enhances the delivery of the information to the reader. This is not an easy thing to do, but you have been very, very successful at it."

Ira David Levin, heart patient, 
Rome, Italy

"Within the pages of Beat Your A-Fib, Dr. Steve Ryan, PhD, provides a comprehensive guide for persons seeking to find a cure for their Atrial Fibrillation."

Walter Kerwin, MD, Cedars-Sinai Medical Center, Los Angeles, CA


Understanding the EKG Signal

By Steve S. Ryan, PhD

Video: Cardiac Conduction System and its Relationship with ECG. Go to video.

An electrocardiogram, ECG (EKG), is a test used to measure the rate and regularity of heartbeats, as well as the size and position of the chambers, the presence of any damage to the heart, and the effects of drugs or devices used to regulate the heart.

The ECG signal strip is a graphic tracing of the electrical activity of the heart. It measures the length of time it takes for the initial impulse to fire at the Sinus Node and then ends in the contracting of the Ventricles.

Schematic diagram of normal sinus rhythm for a human heart as seen on ECG; Public Domain image;

Schematic diagram of normal sinus rhythm for a human heart as seen on ECG

The first upward pulse of the EKG signal, the P wave, is formed when the atria (the two upper chambers of the heart) contract to pump blood into the ventricles. In A-Fib you will see many “fibrillation” beats instead of one P wave. A characteristic sign of A-Fib is the absence of a P wave in the EKG signal.

The next large upward spike segment, the QRS Complex, is formed when the ventricles (the two lower chambers of the heart) are contracting to pump out blood. The normal duration (interval) of the QRS complex is between 0.08 and 0.10 seconds.

The next section, the ST segment, measures the end of the contraction of the ventricles to the beginning of the rest period before the ventricles begin to contract for the next beat.

The next slight rising section, the T wave, measures the resting period of the ventricles.

These pulses are caused by the movement of positively and negatively charged ions (sodium, calcium, potassium, magnesium) through proteins called ion channel receptors. (For an excellent discussion and explanation of the science behind the movement of these chemical ions, see Restart Your Heart by Dr. Aseem Desai, p. 21.)

ECG (EKG) Strip: Atrial Fibrillation

In the case of Atrial Fibrillation, the consistent P waves are replaced by fibrillatory waves, which vary in amplitude, shape, and timing (compare the two illustrations below).

ECG tracing of normal heart rhythm and heart in A-Fib; Copyright 2012 A-Fib, Inc.

© 2012 A-Fib, Inc.

ECG recorder: special graph Paper

The output of an ECG recorder is a graph (or sometimes several graphs, representing each of the leads) with time represented on the x-axis and voltage represented on the y-axis. A dedicated ECG machine would usually print onto graph paper which has a background pattern of 1mm squares (often in red or green), with bold divisions every 5 mm in both vertical and horizontal directions.

Diagram of electrocardiogram paper; Public Domain image

Diagram of electrocardiogram paper.

Video: Cardiac Conduction System and its Relationship with ECG‬

Click for Video: Cardiac Conduction System

Interpreting a ECG strip involves counting the squares of the tracing. For example, by counting the squares of a heart in Normal Sinus Rhythm, you can calculate the heart rate.

Video: Cardiac Conduction System and its Relationship with ECG‬

Animation with narration about the heart’s conduction system. Schematic diagram and explanation of normal sinus rhythm for a human heart as seen on ECG (3:34 min.) Click on image to go to the video page.

Resources & Photo Credits for this article

• Schematic diagram of normal sinus rhythm for a human heart as seen on ECG (with English labels). Wikimedia Common, Public Domain. Last accessed April 13, 2014, URL: http://commons.wikimedia.org/wiki/File%3ASinusRhythmLabels.svg

• Diagram of electrocardiogram paper. Public Doman. Wikipedia.org. Last accessed April 13, 2014, URL: http://en.wikipedia.org/wiki/File:ECG_Paper_v2.svg

• Schematic diagram of normal sinus rhythm for a human heart as seen on ECG (with English labels). Wikimedia Common, Public Domain. Last accessed April 13, 2014, URL: http://commons.wikimedia.org/wiki/File%3ASinusRhythmLabels.svg

• Diagram of electrocardiogram paper. Public Doman. Wikipedia.org. Last accessed April 13, 2014, URL: http://en.wikipedia.org/wiki/File:ECG_Paper_v2.svg

Updated August 2020

Back to top

Return to Diagnostic Testing

If you find any errors on this page, email us. Y Last updated: Wednesday, August 26, 2020

 

Related Posts

Follow Us
facebook - A-Fib.comtwitter - A-Fib.comlinkedin - A-Fib.compinterest - A-Fib.comYouTube: A-Fib Can be Cured! - A-Fib.com

We Need You Help A-Fib.com be self-supporting-Use our link to Amazon  

A-Fib.com is a
501(c)(3) Nonprofit



Your support is needed. Every donation helps, even just $1.00.



A-Fib.com top rated by Healthline.com since 2014 

Home | The A-Fib Coach | Help Support A-Fib.com | A-Fib News Archive | Tell Us What You think | Press Room | GuideStar Seal | HON certification | Disclosures | Terms of Use | Privacy Policy