"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."

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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."

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Terry Traver, former A-Fib patient

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

Left Atrial Appendage heart illustration; Source: Boston Scientific Inc. educational brochure

The Role of the Left Atrial Appendage (LAA) & Removal Issues

By Steve S. Ryan, PhD

In the first trimester or two of our time in the womb, The Left Atrial Appendage (LAA) was originally our left atrium (LA). When the final real Left Atrium (LA) formed gradually from the conjunction and evolutionary development of the four pulmonary veins, the actual LA chamber grew and ballooned out, pushing the smaller remnant LA up to the left top of the Left Atrium where it became became known as the Left Atrial Appendage (LAA) with its own functions and behaviors.

But as we age and as heart disease/A-Fib, etc. start to set in, the LAA can turn into “the most lethal, no longer essential appendage in the human anatomy.” (Thanks to Shannon Dickson for these insights about the LAA.)

One considered advantage of the Mini-Maze operations is that the Left Atrial Appendage (LAA) is closed or cut off. Most A-Fib blood clots which cause stroke come from the Left Atrial Appendage. By closing off the LAA, most but not all risk of stroke is eliminated even if you are still in A-Fib.

Failure to Completely Close Off the LAA is Common

However, in a study by Surgeon s, “both suture exclusion and stapler exclusion had extraordinarily low success rates. In fact, none of the patients with stapler exclusion had successful closure…This study presents clear evidence of the inadequacy of these techniques.”1

According to Dr. Marc Gillinov of the Cleveland Clinic, staplers “can be hard to apply to the appendage and tend to leave a little cul-de-sac and also cause bleeding and tearing, so they are not particularly safe or effective.”2

However, the AtriClip device (FDA approved June, 2010) makes it much easier for surgeons to close off the LAA during open heart surgery. The surgeon positions the rectangular-shaped device around the LAA and then closes it like a clamp. Blood no longer flows into and out of the Left Atrial Appendage.3 

AtriCure has developed a version of the AtriClip which can be used in Mini-Maze surgery.

Should the LAA be routinely cut out, stapled shut or closed off in all A-Fib patients?

Some question the need or benefit of removing the Left Atrial Appendage (LAA) if someone is no longer in A-Fib.

The rationale for closing off the LAA is that, in case the operation fails which happens occasionally, the patient is still protected from having an A-Fib stroke. 90%-95% of A-Fib strokes come from clots which originate in the LAA. In A-Fib, blood stagnates in the LAA and clots tend to form.

Another important consideration, even if a person is no longer in A-Fib, is that closing off the LAA may still prevent a stroke. The LAA is where most clots originate. If a surgeon is already working on the heart, why not close off the LAA and reduce the patient’s chance of having a future stroke? (If a surgeon didn’t close off the LAA, they could be sued if a patient later had a stroke, even if the patient was no longer in A-Fib.) Life (no stroke) is more important for most people than a possible reduced exercise intolerance.

In the future even people without A-Fib may have their Left Atrial Appendage closed off if it prevents or reduces the risk of a stroke. This may become a way to prevent stroke in older people, particularly women, who are more at risk of stroke as we age. There are currently a variety of devices, surgical and non-surgical, which can do this. LAA closure may become an important new way to reduce strokes, particularly in the elderly.

Functions of the Left Atrial Appendage

Some question the need or benefit of removing the Left Atrial Appendage (LAA) if someone is no longer in A-Fib. For a patient made A-Fib free, would their heart function better or more normally if they still had their LAA?

The LAA functions like a reservoir or decompression chamber or a surge tank on a hot water heater to prevent surges of blood in the left atrium when the mitral valve is closed.4Without it there is increased pressure on the pulmonary veins and left atrium which might possibly lead to heart problems later.


Cutting out or stapling shut the LAA also reduces the amount of blood pumped by the heart and may result in exercise intolerance for people with an active life style. (In dogs the LAA provides 17.2% volume of blood pumped.5) This is usually not a problem for patients with Persistent (Chronic) A-Fib, whose LAA has stopped contracting along with the fibrillating atrium. Cutting out or stapling shut the LAA won’t affect their cardiac output. But this may not be the case for patients with Paroxysmal A-Fib who still have large amounts of normal rhythm and whose LAA still functions normally.

But would a non-functioning LAA return to normal when someone with, for example, longstanding persistent (Chronic) A-Fib becomes A-Fib free?

The author isn’t aware of any surgeons (or EPs) who do pre- and post-LAA closure measurements of exercise ability, heart pumping function, etc. with and without the LAA.

(When doctors do a TEE [Transesophageal Echocardiogram] of the LAA of someone in A-Fib, the LAA doesn’t move at all and blood does not move. Doctors refer to this as “SMOKE” which is shorthand for Spontaneous Echo Contrast. The blood not moving looks like smoke inside the LAA.)

The LAA also has a high concentration of Atrial Natriuretic Factor (ANF) granules which help to reduce blood pressure.6Some preliminary research indicates that when the LAA is closed or cut off, the Right Atrial Appendage produces more ANF to compensate for the lost of the LAA.

Editor’s comment: If you are thinking of having a Cox Maze or Mini-Maze, discuss removing the LAA with the surgeon. Ask if they close off the Left Atrial Appendage and with what: sutures, stapler or the AtriClip.

Posted June 2013

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Return to Index of Articles: Maze, Mini-Maze, Convergent, LAA Closure Surgeries

Last updated: Sunday, February 15, 2015

References    (↵ returns to text)
  1. Damiano, Jr., RJ. “What Is the Best Way to Surgically Eliminate the Left Atrial Appendage?” Journal of the American College of Cardiology 2008, Sept. 9; Vol. 52, No. 11:930-1.
  2. AtriCure’s AtriClip system receives FDA 510(k) clearance (press release). June 14, 2010. 
  3. AtriCure’s AtriClip system receives FDA 510(k) clearance (press release). June 14, 2010.
  4. Al-Saady, N M, et al.  Left atrial appendage: structure, function, and role in thromboembolism
  5. Hondo T. et al. “The Role of the left atrial appendage. A volume loading study in open-chest dogs.” Jpn Heart J 1995 Mar;36(2):225-34.  http://www.ncbi.nlm.nih.gov/pubmed/7596042
  6. Atrial natriuretic peptide. Wikipedia.org. Last accessed April 13, 2014, URL: http://en.wikipedia.org/wiki/Atrial_natriuretic_peptide.

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