Catheter Ablation Reduces Stroke Risk Even for Higher Risk Patients
by Steve S. Ryan, April 2015
In a study of nearly 38,000 people, patients with A-Fib who had a catheter ablation had about as many strokes as the people without A-Fib, while people on just medication had about twice as many strokes. (This isn’t a surprising finding. If you no longer have A-Fib, by definition you can’t have an A-Fib stroke.)
But what is surprising is that even patients at greater risk of stroke had a reduced stroke risk after catheter ablation. “Across all CHADS2 profiles and ages, A-Fib patients with ablation had a lower long-term risk of stroke compared to patients without ablation.” Even those at higher risks of stroke had a reduced risk of stroke.
Catheter Ablation Reduces Stroke Risk to That Of A Normal Person
And, more importantly, if someone had a catheter ablation, stroke risk decreased to that of a normal person. “A-Fib ablation patients had similar long-term risks of stroke across all CHADS2 profiles and ages compared to patients with no history of A-Fib.” “…freedom from A-Fib was the strongest predictor of stroke-free survival.”
Warfarin Not Needed After Successful Catheter Ablation
Some patients after a catheter ablation are still put on warfarin-for-life depending on their CHADS2 score. But research indicates that “A-Fib patients after ablation with moderate to high risk CHADS2 scores in which warfarin was discontinued do not show a higher risk of stroke compared to those in which warfarin is continued.”1
This study is medical breakthrough news, similar to another important study in which a successful catheter ablation reduced by 60% the expected rate of cardiovascular mortality. (See Live Longer—Have a Catheter Ablation.)
For anyone who has had a successful catheter ablation or who is thinking of having one, this study also is a game changer!
Even if you are at a theoretical high risk of stroke (high CHADS2), you don’t have to be on warfarin for the rest of your life after a successful catheter ablation. A successful catheter ablation reduces your stroke risk to that of a normal person (though obviously normal people do have strokes).
We already know that a catheter ablation significantly improves our well being. We certainly feel healthier in sinus rhythm. Few other medical procedures produce such a dramatic and nearly immediate improvement in our quality of life. This study confirms the long-term benefits of catheter ablation even for people who are sicker.
We don’t have to live a life on meds! A-Fib can be cured by a catheter ablation. And when you are made A-Fib free, not only do you feel better, but your risk of stroke is reduced to that of a normal person! This is terrific news for the A-Fib community.
Last updated: Tuesday, January 12, 2016
- Themistoclakis, S. et al. The risk of thromboembolism and need for oral anticoagulation after successful atrial fibrillation ablation. J Am Cardiol. 2010;55:735-743. http://content.onlinejacc.org/article.aspx?articleid=1140481 doi:10.1016/j.jacc.2009.11.039↵
23. “During an ablation, how much danger is there of developing a clot? What are the odds? How can these clots be prevented?” [Someone emailed me that she suffered both a stroke and a blood clot in her lung during her ablation. She is recovering. Why did this happen?]
Depending on how long one has been in A-Fib, clots may have developed in the heart, then be dislodged during the ablation.
Most centers do a TEE (Transesophageal Echocardiogram) before the ablation to check if there are any clots in your heart. If they find any, they administer anticoagulants to dissolve the clots before the ablation. If your center or doctor doesn’t plan to do a TEE before your ablation, you should probably go somewhere else.
However, most clots during an ablation come from RF charring. The heat from an RF catheter chars the heart tissue. Some of the char breaks off and becomes a clot. This problem has been minimized over the years by the use of irrigated tip catheters and the administering of heavy-duty anticoagulants like heparin during the ablation. The skill and expertise of the doctor also play an important role. But even in the best of hands, accidents can still happen.
Your chances of developing a clot during an ablation vary according to the institution and doctor. (You should ask about this the medical center or EP’s rate of clots forming when considering an ablation.) For example, the Bordeaux Group in 2010 reported an embolic event (stroke) rate of 0.2%.
With the newer technique of CryoBalloon (freezing) ablation, there is no charring and theoretically no risk of developing a clot from charring.
Last updated: Wednesday, February 4, 2015
Return to FAQ Catheter Ablation and Maze Surgeries
Atrial Fibrillation patients often search for unbiased information and guidance about medicines and drug therapy treatments. These are answers to the most frequently asked questions by patients and their families. (Click on the question to jump to the answer.)
11. “I am on Coumadin (warfarin) to thin my blood and prevent A-Fib blood clots. Do I now need to avoid foods with Vitamin K which would interfere with the blood thinning effects of Coumadin?” UPDATED
12. “The A-Fib.com web site claims that an A-Fib stroke is often worse than other causes of stroke. Why is that? If a clot causes a stroke, what difference does it make if it comes from A-Fib or other causes? Isn’t the damage the same?“
16. “I have to be on aspirin for stroke prevention. Which is better—the low-dose baby aspirin (81 mg) or a high dose (325 mg)? Should I take the immediate-release (uncoated) or the enteric-coated aspirin?”
17. “I don’t want to be on blood thinners for the rest of my life. I’ve had a successful catheter ablation and am no longer in A-Fib. But my doctor says I need to be on a blood thinner. I’ve been told that, even after a successful catheter ablation, I could still have “silent” A-Fib—A-Fib episodes that I’m not aware of. Is there anything I can do to get off of blood thinners?“
21. “I”ve read about a new anticoagulant, edoxaban, as an alternative to warfarin (Coumadin) for reducing risk of stroke. For A-Fib patients, how does it compare to warfarin? Should I consider edoxaban instead of the other NOACs?”
Last updated: Wednesday, May 25, 2016
15. “How long do I have to be in A-Fib before I develop a clot and have a stroke?”
When blood is stagnant and not being pumped out of the left atrium, a clot can form. When the left atrium starts beating again, this clot can be pushed downstream into the left ventricle which then pumps this clot into the legs, lungs, brain or other organs causing an ischemic stroke.
But these clots aren’t formed instantly. It takes a while for stagnant blood to pool and clot. For example, if you have a ten minute attack of A-Fib, conventional wisdom says it’s unlikely a clot will develop.
The American College of Chest Physicians recommends that anticoagulation therapy be started after two days. But not everyone is in agreement that it takes at least two days of being in A-Fib for a clot to form. Dr. Antonio Gotto in Bottom Line Health says it takes one day for a clot to form, “There’s an increased risk for stroke if the irregular heartbeat continues for more than 24 hours.” (Some doctors are of the opinion that it takes as little as 5 1/2 hours of A-Fib for a clot to develop.)
Return to FAQ Drug Therapies
Last updated: Monday, September 28, 2015
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
Also see my article, Left Atrial Appendage May be Important for Heart Repair
Also see my article, Left Atrial Appendage May be Important for Heart Repair
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.
Some question the need or benefit of removing the Left Atrial Appendage (LAA) if someone is no longer in A-Fib.
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
Last updated: Sunday, February 15, 2015
- 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.↵
- AtriCure’s AtriClip system receives FDA 510(k) clearance (press release). June 14, 2010. ↵
- AtriCure’s AtriClip system receives FDA 510(k) clearance (press release). June 14, 2010.↵
- Al-Saady, N M, et al. Left atrial appendage: structure, function, and role in thromboembolism↵
- 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↵
- Atrial natriuretic peptide. Wikipedia.org. Last accessed April 13, 2014, URL: http://en.wikipedia.org/wiki/Atrial_natriuretic_peptide.↵
Cardioversion for Atrial Fibrillation
Your doctor may recommend a cardioversion to restore your heart to normal sinus rhythm (NSR). There are two types of cardioversion: chemical and electrical. Cardioversion through the use of drugs is called chemical cardioversion. Electrical cardioversion uses a low-voltage, timed electrical shock to restore normal rhythm.
Most cardioversions are planned and scheduled several weeks in advance.
On the other hand, if your A-Fib is so irregular and rapid that it is life threatening, you may be sent to the emergency room, given the intravenous anticoagulant Heparin, and an electrical cardioversion performed.
The goal of chemical cardioversion is to make your heart beat regularly (in normal sinus rhythm). It is usually done in a hospital. Some combination of medications (see Treatment/Drug Therapies) is administered intravenously, such as Cardizem, verapamil, ibutilide, or adenosine (a class V antiarrhythmic agent). Doctors monitor you closely for adverse side effects.
Chemical cardioversion is often done in combination with Electrical Cardioversion described below.
Electrical Cardioversion is a medical term for giving your heart a low-voltage electrical shock to synchronize it, that is, to make it beat regularly (in normal sinus rhythm). It is often used in combination with Chemical Cardioversion.
Note: Electrical cardioversion is not the same as Defibrillation. In defibrillation, doctors use high-voltage shocks to treat life-threatening arrhythmias or a heart that has stopped.
During Electrical Cardioversion you are anesthetized and are unconscious when you receive the shock. The shock causes the signal producing areas of your heart to discharge all at once. This stops all electrical activity in your heart momentarily, hopefully allowing your normal heart rhythm to take over. Usually only one shock is required to restore NSR.
Low Risk Treatment But High Risk of Clots Forming
Electrical Cardioversion is considered a low risk procedure. But it is a ‘shock’ to the body and requires general anesthesia. (It’s like a mini electrocution. The metal paddles or patches, for example, can potentially leave burn marks on the chest.)
Cardioversion does carry a high risk of forming clots and causing stroke.2
Why? An Electrical cardioversion “stuns” your heart along with your Left Arial Appendage (LAA). Clots may form in the LAA while your heart is stunned and not beating. The clot can break away and enter the blood stream with the potential of causing a stroke. (The LAA is where most A-Fib clots originate.)
To dissolve potential clots, your doctor will have you take an anticoagulant like warfarin (Coumadin) before the treatment and in the three to four weeks following treatment.
While on warfarin (Coumadin), your blood will be tested for how long it takes to clot (a prothrombin time test, PT). The goal is to keep your INR (International Normalized Ratio) score between 2.0 and 3.0. Your dosage will be adjusted if necessary. You may have to have your blood tested weekly until your doctor determines you are in the proper INR range.
Success Rate of Cardioversion
Electrical Cardioversion (often combined with Chemical Cardioversion) is considered a standard, routine, low risk treatment option, particularly for recent onset A-Fib patients. If your A-Fib has just started, it may be a momentary aberration; and an Electrical Cardioversion may correct it.
Cardioversion has a very high initial success rate, returning up to 95% of A-Fib patients to NSR.
While the conversion rate is high, recurrence of A-Fib is high too. As few as 23% of patients remain in normal sinus rhythm for more than one year post-procedure. For most, their A-Fib returns within the first five days.4
Are Repeated Electrical Conversions Dangerous?
People with A-Fib often ask, “How often can I be Electrical Cardioverted? Does it ever become counterproductive or dangerous?” Right now we just don’t know the answer to this question.
Former Senator and NBA basketball player Bill Bradley had three successful Electrical Cardioversions from 1996-1998 without any apparent ill effects.5 I’ve heard of an A-Fib patient who received an Electrical Cardioversion once a month for a year without any apparent problems.
VIDEO 2: Watch an actual Electrical Cardioversion recorded at the patient’s request: “Me Being Cardioverted” posted by reddy321.6But be advised: the patient in this video is partially awake (this is not the norm). This video is a bit unsettling to watch (but not dangerous or painful for the patient).
Don’t Be Frightened
Don’t let this type of video frighten you. It may look and sound traumatic, but Electrical Cardioversion is in fact non-invasive and is one of the easiest and safest short term treatments available for A-Fib.
And don’t let TV shows with emergency room scenes frighten you either. In fact, those scenes are usually depicting defibrillation, not cardioversion (defibrillators use high-voltage shocks to treat a heart that has stopped beating).
In her Personal Experiences story, Kris tells of accidentally being awake during an electrical cardioversion (see Personal Experiences story #37). According to Kris, the shock is relatively mild compared to what you often see portrayed in medical dramas on TV.
Last updated: Wednesday, April 6, 2016
- VIDEO 1: Short animation explaining electrical cardioversion when in Atrial Fibrillation. YouTube video posted by eMedTV; Last accessed Oct 12, 2014; URL: http://www.youtube.com/watch?v=-jkhQ5Tl2fs↵
- Haines, D. “Atrial Fibrillation: New Approaches in Management.” Un. of Virginia multi-media presentation, 1999, p.2. http://www.a-fib.com/HainesUnOfVirginiaAtrialFibrillation.htm↵
- Boos C , More RS, Carlsson J. Persistent atrial fibrillation: rate control or rhythm control. BMJ 2003;326:1411–2.↵
- Gorman, Christine, “A Candidate’s Racing Heart,” TIME, Sunday, Dec. 12, 1999. http://www.time.com/time/printout/0,8816,35831,99.html↵
- VIDEO 2: Me Being Cardioverted YouTube video; Last accessed February 22, 2013; URL: http://www.youtube.com/watch?v=2nsN0vdXZuY&feature=fvw.↵