Ablation for afib when atria is enlarged

[va_tony]

I've read that a common cause of atrial fibrillation is an enlarged atrium, as in my case.  Apparently, the greater surface area allows the formation of a requisite number of multiple reentrant wavelets to support the afib. In my case, my left atrium has been measured at 5.2 cm. What is the success rate of rf ablation at the Cleveland Clinic for those having afib with such large atrial enlargement? Assuming the ablation is successful in removing all stray foci, wouldn't the continued presence of the enlarged atrium make the patient susceptible to an easy return of afib sometime in the future, whenever another stray foci develops?

Is there an overall strategy that one can follow to reduce the size of the atrium? When mine was first measured at 5.2 cm, I had been in persistent afib for several months and my blood pressure was 140/95. I'm now in normal sinus rythym with the help of Rythmol (episodes of afib still occur about once a month but self terminate after several hours) and my bp is now 130/80 by taking altace and tiazac. I also take coumadin. After six months of being in NSR, losing twenty pounds (I'm 6' 5" and currently 260 lbs) and with the lower bp, an echo still showed my atrium to be about 5.2 cm. This was disappointing because I thought the weight loss, bp drop and return to NSR would cause the atrium to contract somewhat.  I do also have some slight mitral valve regurgitation but my cardiologist feels that this wasn't the cause of the enlargement. Any comment?

[CCF-M.D.-RCJ]

va_tony,

Thanks for the well-informed post.

Q1:" What is the success rate of rf ablation at the Cleveland Clinic for those having afib with such large atrial enlargement? "

Our success rate is 80-85% for all-comers, but some factors certainly decrease our success rate.  Chronic afib and atrial enlargement are two of those factors.  An LA size of 5.2 cm is certainly large, but we have seen much larger.  I don't have the data available to me to tell you how the success rate drops for each increment in LA size.

Q2:"wouldn't the continued presence of the enlarged atrium make the patient susceptible to an easy return of afib sometime in the future, whenever another stray foci develops?"

Yes.  To help counter this fact, many centers add a "substrate modification" portion to the ablation procedure to help counterbalance the disadavantage caused by the atrial enlargement.

Q3:"Is there an overall strategy that one can follow to reduce the size of the atrium?"

Treatment of high blood pressure and maintenance of sinus rhythm are two good first steps.  After that it's the usual things like stopping swearing, calling your mom, going to church (temple, synagogue, mosque), etc.

Q4:"This was disappointing because I thought the weight loss, bp drop and return to NSR would cause the atrium to contract somewhat. I do also have some slight mitral valve regurgitation but my cardiologist feels that this wasn't the cause of the enlargement. Any comment?"

Give the atrium a chance!  It may take some time to remodel.  Also, getting a good quality echo may help ensure that the valvular regurgitation is not contributing.  Make sure that the cardiologist feels the echo was of sufficient quality.

Best of luck.

[va_tony]

Thank you Dr. RCJ for answering my questions and providing some useful insights.  I hope to learn more about "substrate modification" by doing further reading on the subject. Your advice to incorporate anger management in the overall strategy for atrial reduction (by not swearing, etc.) is, I believe, the most appropriate advice for me. I'm definitely a type-A and known to be too tense and impatient at times. Was this particular character flaw so obvious in my writing? I've tried in the past but I'll redouble my efforts to lighten up as you suggest. Thanks again for the helpful remarks.

Thanks also to dquenzer (doug), who suggested contacting medhelp.org on the Arrhythmia Forum of HeartCenterOnline. Doug also advised on the best time to call, which helped me get through on my second try!  Hi Momto3 (alias conniezee),also from HeartCenterOnline. I can see why Momto3 and dquenzer post here frequently.  This is a neat forum!

[SteveB47]

I too would be interested in your (anybodys) comments on substrate modification.  Is this a single procedure or a series of procedures?  Can this be done at the time of ablation, or another visit?
Thanks.
Steve

[va_tony]

Steve,

I performed a google search. If I understand correctly, "substrate modification" seems to be an rf ablative procedure that can be performed at the same time as the usual ablative surgery - - i.e., simultaneously with ablation of stray foci and pulmonary vein isolation (see http://www.ipej.org/0304/knight.htm ).   It consists of making long linear rf-induced lesions on the atrium to electrically isolate different portions and so stop the formation of reentrant wavelets (see http://www.bnk.de/herz/en/1926_3121.htm).

Tony

[SteveB47]

Wouldn't this cause an excessive amount of scar tissue? Would it interfere with the functionality of the atria?

[va_tony]

Steve,  

    I also wondered about this.  The same objections must apply to the Maze procedure, since that involves scarring the external surface of the atria. Electrically isolating different portions of the atrium would, at first glance, seem to spoil its ability to pump.  One article I came across seemed to imply that an electrical pulse traverses the lesion with a time delay rather than being blocked. Unfortunately, the article just mentioned that fact in passing.  A time delay might still allow atrial pumping (depending on the time scales involved) yet spoil the ability of reentry loops to sustain themselves. As for scarring, that's known to be a source of extraneous electrical pulses that are potential triggers for PACs. Yes, this certainly raises a number of follow-up questions.

   Are there any posters out there who have had "substrate modification" performed during their ablations?

Tony

[Momto3]

You are right!  I post here because this is an awesome forum. There is an incredible amount of good information, and the doctors are terrific. I don't really post much on the other website as I prefer the diaglogue of this one.  Good luck on your search for information.  Have you tried the archives here? Lots of reading for sure.  connie