"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

"Your book [Beat Your A-Fib] is the quintessential most important guide not only for the individual experiencing atrial fibrillation and his family, but also for primary physicians, and cardiologists."

Jane-Alexandra Krehbiel, nurse, blogger and author "Rational Preparedness: A Primer to Preparedness"


"Steve Ryan's summaries of the Boston A-Fib Symposium are terrific. Steve has the ability to synthesize and communicate accurately in clear and simple terms the essence of complex subjects. This is an exceptional skill and a great service to patients with atrial fibrillation."

Dr. Jeremy Ruskin of Mass. General Hospital and Harvard Medical School

"I love your [A-fib.com] website, Patti and Steve! An excellent resource for anybody seeking credible science on atrial fibrillation plus compelling real-life stories from others living with A-Fib. Congratulations…"

Carolyn Thomas, blogger and heart attack survivor; MyHeartSisters.org

"Steve, your website was so helpful. Thank you! After two ablations I am now A-fib free. You are a great help to a lot of people, keep up the good work."

Terry Traver, former A-Fib patient

"If you want to do some research on AF go to A-Fib.com by Steve Ryan, this site was a big help to me, and helped me be free of AF."

Roy Salmon Patient, A-Fib Free; pacemakerclub.com, Sept. 2013

Understanding the EKG Signal

By Steve S. Ryan, PhD

For Instructional Video, see below.

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.

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 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.

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.

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.

To learn more about reading an ECG strip, see an excellent handout from the St. Petersburg College, School of Nursing, ‘EKG Interpretation: The Easy Rs‘.

Video: Cardiac Conduction System and its Relationship with ECG‬

Video: Cardiac Conduction System and its Relationship with ECG‬

Instructional 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)

Taken from Cardiovascular System. Published on YouTube on Jan 14, 2014 Posted by medo yaser

References & Photo Credits for this article

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If you find any errors on this page, email us. Y Last updated: Saturday, February 18, 2017


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