"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


With a Stroke Risk Score of 1—Do You Really Need an Anticoagulate?

Background readings: The CHADS2 & CHA2DS-VASc Stroke-Risk Grading Systems, and my 2015 AF Symposium reports: Dr. Hugh Calkins’ remarks on the AHA/ACC/HRS A-Fib Treatment Guidelines, and Dr. Peter Kowey’ talk, All Anticoagulants Cause Bleeding;

Stroke Risk Grading System

Current European guidelines for assessing A-Fib stroke risk state that a patient with a CHA2DS2-VASc score of 1 (on a scale of 0 to 10, no risk to high risk) should be taking novel oral anticoagulants (NOACs). But a recent Swedish study contradicts this.

A Swedish National Patient Registry study looked at 140,420 patients with A-Fib who had “stroke events”. For women with a score of 1, annual stroke rates varied between 0.1% and 0.2% (depending on which “event” definition was used). For men, the stroke rate varied between 0.5% and 0.7%.

The researchers stated, “These low annual event rates call into question the need for or use of oral anticoagulant therapy in these low-risk patients.”

Similar insights were found in a study of the National Health Insurance Research Database in Taiwan among 186,570 A-Fib patients not on antiplatelet or anticoagulant therapy. Researchers concluded that “not all risk factors in CHA2DS2-VASc score carry an equal risk.”

What this Means for A-Fib Patients

Taking an anticoagulant isn’t like taking vitamins. No one should be on anticoagulants unless they have an actual risk of stroke.

In the past, only a CHADS2 or CHA2DS2-VASc score of 2 or higher would indicate someone should be on a blood thinner such as warfarin. (Note: This single digit change creates an extremely large population of customers for the pharmaceutical companies and a quite lucrative business. Is this just a coincidence?)

While the U.S. guidelines are an improvement over the European guidelines, based on the Swedish and Taiwan studies, neither the U.S. nor European guidelines recognize that someone with a score of 1 probably shouldn’t be on anticoagulants at all.

All anticoagulants cause bleeding (that’s how they work.) So they are inherently dangerous. Why run the risk if you don’t need to?

Taking an anticoagulant isn’t like taking a daily vitamin. No one should be on anticoagulants as a precaution, there should be an actual risk of stroke.

The Decision: To Take an Anticoagulant or Not?

When you have atrial fibrillation, whether or not to be on an anticoagulant to reduce your risk of stroke (and which one to take) is perhaps the most difficult decision for you and your doctor. That decision should be based on actual risk factors and not on a “precautionary” approach.

Remember, this decision means taking medication as long as you still have A-Fib. For some patients that’s a lifetime.

References for this article

The CHADS2 & CHA2DS-VASc Stroke-Risk Grading Systems

Stroke-Risk Grading Systems

Stroke-Risk Grading Systems

By Steve S. Ryan, PhD, Updated Nov 2014

In the US, doctors use what is called a CHADS2 stroke-risk grading system to help estimate the risk of stroke in patients with atrial fibrillation. A high CHADS2 score corresponds to a greater risk of stroke, while a low CHADS2 score corresponds to a lower risk of stroke. The CHADS2 score is simple and has been validated by many studies.

The patient’s stroke risk, i.e., their CHADS2 score, is estimated by adding together the points that correspond to the patient’s conditions.

“C” Congestive Heart Failure Score = 1

“H” Hypertension Score = 1

“A” Age over 75 Score = 1

“D” Diabetes Score = 1

“S2” Previous Stroke or TIA Score = 2

 A CHADS2 score of 2 or over would indicate someone should be on a blood thinner such as warfarin.

The CHADS2 score has been superseded in clinical use by the CHA2DS2-VASc score that is designed to give a better stratification of low-risk patients. It utilizes the same 5 major risk factors considered by CHADS2 but assigns a score of ‘2’ for patients older than 75 years, and adds 3 new risk factors: a history of vascular disease, age 65-74 years, and female sex which increase stroke risk. But according to the original study, “there was no statistically significant difference found between the CHA2DS2-VASc and CHADS2 risk stratification schema in predicting TE events”.

A-Fib Stroke Risk Calculators

CHAD2DS2VAC Medium 100 pix at 96 resUse this link to calculate your A-Fib stroke risk using the CHADS2 Calculator
Use this link to calculate your A-Fib stroke risk using the CHA2DS2-VASc Calculator

Classification of CHADS2 vs CHA2DS-VASc

In both scoring systems, a score of 0 is “low” risk of stroke, 1 is “moderate”, and any score above 1 is a “high” risk. The CHA2DS2-VASc system has three more variables and therefore will classify a greater number of patients into a high-risk group.

Editor’s comment: There is some controversy about the increased stroke risk for females. See articles on Dr. John M’s blog post and Aging Well magazine.
See also our article: Women in A-Fib Not at Greater Risk of Stroke, and The New CHA2DS2-VASc Guidelines and the Risks of Life-Long Anticoagulation Therapy.

References for this article

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Last updated: Thursday, September 3, 2015

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