"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

AF Symposium 2016

Thickening of Left Atrium and Amount of Fibrosis Predicts Outcome of A-Fib Ablation

by Steve S. Ryan, PhD

Dr. Nassir F. Marrouche

Dr. Nassir F. Marrouche

Dr. Nassir F. Marrouche, University of Utah (CARMA), is known for ground-breaking, thought-provoking research using MRI. His presentation was entitled “Atrial and Ventricular Myopathy: A Novel risk predictor for stroke and cardiovascular events.”

Amount of Fibrosis Better Predictor of Stroke Risk (and Heart Attack)

Dr. Marrouche began by showing how today’s stroke guidelines (CHADS2 or CHA2DS2-VASc) are mediocre predictive tools overall, according to most studies. Whereas atrial fibrosis detected by Delayed Enhancement-MRI (DE-MRI) is a better predictor of stroke risk.

DE-MRI stands for Delayed Enhancement Magnetic Resonant Imaging.

In Dr. Marrouche’s study, patients with more than 21% fibrosis had a 19.6% risk of stroke while those with under 8.5% fibrosis had only a 1% risk. The more fibrosis, the greater risk of clots forming in the Left Atrial Appendage (LAA).

In a study by King, higher levels of fibrosis were associated with ‘Major Adverse Cardiac Events’ (MACE), not only stroke but heart attack and deep vein thrombosis (a blood clot within a vein).

Cardiomyopathy and Fibrosis

Dr. Marrouche showed slides of normal atrial myocytes (muscle cells) vs. examples with extensive fibrosis where collagen replaced most of the red myocytes (which store oxygen until needed for muscular activity).

This is an important finding which may change the way we look at fibrosis.

This fibrosis correlated with abnormality of the atria (atrial myopathy) and deterioration of the ability of heart muscles to contract (cardiomyopathy). This is an important finding which may change the way we look at fibrosis.

(For further information on Dr. Marrouche’s work, see Higher Fibrosis at Greater Risk of Stroke and Precludes Catheter Ablation.)

Fibrosis/Myopathy Correlates with Atrial Strain

Dr. Marrouche showed slides of how the left atrium of an A-Fib patient with extensive fibrosis worked much harder to pump and had nearly three times more strain than a patient with mild fibrosis. (This may be why the left atrium often stretches and expands in remodeling.)

A-Fib Thickens Left Atrial Shape

In another ground-breaking observation, Dr. Marrouche showed slides of how the shape of the left atrium (LA) gets thicker as one progresses from no-A-Fib to paroxysmal to persistent A-Fib. In fact, in a study by Bieging, LA shape (thickness) is a strong independent predictor of outcome after AF ablation.

Left Atrial Appendage and Stroke Risk

Dr. Marrouche found that the Left Atrial Appendage (LAA) length, thickness and orientation correlate with stroke risk. These findings open up new avenues of research in A-Fib. Just looking at the LAA might produce an indication of stroke risk, which can be combined with other predictive measures.

Left Ventricular Disease Predicts Recurrence after Ablation Therapy

Some A-Fib patients also have a diseased Left Ventricle (LV) which shows up using ‘Late Gadolinium Enhancement- MRI’ (LGE-MRI). In a study by Suksaranjit, the recurrence rate after an ablation was 69% in patients with Left Ventricular LGE-MRI revealed disease, compared to 38% in patients without LV LGE-MRI. These patients also have more major adverse cardiac and cerebrovascular events.


Dr. Marrouche is now using both the amount of fibrosis and left atrial shape to stage and treat A-Fib patients. The main points we can learn from Dr. Marrouche’s research are:

Fibrosis makes the heart stiff, less flexible and weak, overworks the heart, reduces pumping efficiency and leads to other heart problems.

• Fibrosis puts you are greater risk of a stroke and other vascular problems.
• More fibrosis leads to thickened heart tissue, strains the heart and reduces the ability of the heart muscles to contract.
• A-Fib changes the thickness/shape of the left atrium.
• A-Fib can also change the length, thickness and orientation of the Left Atrial Appendage (LAA).
• Left Ventricular disease may accompany or be caused by A-Fib, be measured by MRI, and predict recurrence after catheter ablation..

What Patients Need To Know

Don’t delay! Your A-Fib leads to fibrosis! A-Fib produces fibrosis which is considered permanent and irreversible. Any treatment plan for A-Fib must try to prevent or stop remodeling and fibrosis.

Caveat: After reading Dr. Marrouche’s research and new insights that atrial fibrosis detected by DE-MRI is a better predictor of stroke risk (than CHADS2 or CHA2DS2-VASc), don’t rush into your EPs office asking about using MRI to diagnose your amount of fibrosis. Not every MRI technician and doctor has the special training and experience necessary to perform Dr. Marrouche’s testing. (And insurance companies may not want to pay for this testing. However, that may soon change.)

References for this article

Return to 2016 AF Symposium Reports by Steve Ryan, PhD

If you find any errors on this page, email us. Y Last updated: Monday, February 22, 2016

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