Markers of Myocardial Damage, Tissue Healing, and Inflammation After Radiofrequency Catheter Ablation of Atrial Tachyarrhythmias

[onlinelibrary.wiley.com]

Markers of Myocardial Damage, Tissue Healing, and Inflammation After Radiofrequency Catheter Ablation of Atrial Tachyarrhythmias

Obviously the goal of a successful ablation is to cause enough scar tissue to cage the firing areas. But how much is enough? How much Myocardial healthy tissue does one need? Many have multiple ablations, each chipping away heart tissue. There must be some accumulated effects down the road in addition to flutter.

This discussion was recently brought up to me at an EP’s office and got me thinking.

Thanks for posting the linked article abstract. I can only speak for myself, but all the literature I have found and been given suggests that it can take up to a year to return to something passing for 'normal' in heart function, heart work capacity, and how well one feels emotionally and physically in general. My EP has a 10-week blanking period, less than half of the time after ablation in this study. I don't know that it is enough, but it is moot in my case as I am having ectopic beats in the eighth week. Empirically, that doesn't bode well for me.

I worry about the tissue separation mentioned. That can't be much more salutary than clots.

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susan.d
Obviously the goal of a successful ablation is to cause enough scar tissue to cage the firing areas. But how much is enough? How much Myocardial healthy tissue does one need?

If taken literally, not sure the questions are answerable. A related question might be: for a given patient, what treatment plan yields the highest functioning atrium N years post, say N=2 years? Nearly everyone seems to be focused on atrial burden (% time spent in fibrillation) as being the metric of atrial function, but I see you are looking beyond that. Anyway I don't know the answers. If I can find again the paper that looks at the atrium's recovery as a function of the extent of ablation, I'll post it. But getting the atrium restored to it's highest function has, in my opinion, more playable factors than ablation extent.

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susan.d
Obviously the goal of a successful ablation is to cause enough scar tissue to cage the firing areas.

FWIW:

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Research Needs and Priorities for Catheter Ablation of Atrial Fibrillation:

[pubmed.ncbi.nlm.nih.gov]

Al-Khatib, Sana M et al.
“Research Needs and Priorities for Catheter Ablation of Atrial Fibrillation: A Report From a National Heart, Lung, and Blood Institute Virtual Workshop.”
Circulation vol. 141,6 (2020): 482-492.
doi:10.1161/CIRCULATIONAHA.119.042706

Page 4:
It is noteworthy that experts recommend defining “successful ablation” as freedom from symptomatic or asymptomatic atrial arrhythmia lasting for >30 seconds within 1 year of follow-up.[9] However, this definition may underestimate the real potential net benefit of AF ablation because many patients who do not meet this definition have a significant reduction in arrhythmia burden and improvement in quality of life and heart function.[19] While standardizing the definition of “successful ablation” is not within the scope of this paper, investigators are encouraged to define it clearly at the inception of any future study.

Edited 2 time(s). Last edit at 09/19/2022 07:14PM by Kwilk.

from 2017:

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Comparisons of the underlying mechanisms of left atrial remodeling after repeat circumferential pulmonary vein isolation with or without additional left atrial linear ablation in patients with recurrent atrial fibrillation
[pubmed.ncbi.nlm.nih.gov]
Yang, Chia-Hung et al.
“Comparisons of the underlying mechanisms of left atrial remodeling after repeat circumferential pulmonary vein isolation with or without additional left atrial linear ablation in patients with recurrent atrial fibrillation.”
International journal of cardiology vol. 228 (2017): 449-455.
doi:10.1016/j.ijcard.2016.11.020

Conclusions: In patients with recurrent AF, a successful repeat CPVI with or without additional LA linear ablation reduced LA size without significant deleterious effects on LA function and mechanical dispersion.

iI is ten years later now, but back in 2013 two authors put it rather bluntly in their review paper:

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Cardiac Remodeling After Atrial Fibrillation Ablation
page 38:
From current evidences, it is still not sufficient to ignore the damage of the left atrial function caused by ablation. Avoidance of over-ablating the unnecessary atrial myocardium is important.

[pubmed.ncbi.nlm.nih.gov]

Lo, Li-Wei, and Shih-Ann Chen.
“Cardiac Remodeling After Atrial Fibrillation Ablation.”
Journal of atrial fibrillation
vol. 6,1 877. 30 Jun. 2013,
doi:10.4022/jafib.877

You found some interesting papers, Kwilk.

One thing to keep in mind with regard to loss of function from an ablation is that the atria only contribute a relatively small amount of pumping action. I've heard 15% discussed as the number that "atrial kick" contributes to cardiac output, but I don't know where that number comes from and don't know if there's any truth to it. Anecdotally, I've had multiple ablations and I have visibly reduced atrial function on ECG, and yet I've noticed no difference in my athletic performance before and after.

Thank you Kwilk. Great links. I just wish I had some of your successful ablations results with minimal performance deficits. Ablation affects individuals uniquely and some, like me, end up not successful and performance drained and more symptomatic.

Ditto what Cary said - I have had two ablations (3 years ago and 16 years ago), both with MORE than just PVI and neither ablation had any negative impact on my physical performance, either day to day or with my windsurfing, golf, hiking, jogging, scuba diving, weightlifting and snow skiing. I am now 77, but don't jog anymore (hip replacement). However, one issue remains, but the source (ablation, age, ?) has surfaced in the last 5 years. Maximal heart rate is only 125, achieved on a maximal stress test. I would like to see it higher.

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Ken
However, one issue remains, but the source (ablation, age, ?) has surfaced in the last 5 years. Maximal heart rate is only 125, achieved on a maximal stress test. I would like to see it higher.

Peter Attia MD & Mike Joyner MD discuss max heart rate in this podcast. Unfortunately I don't have the timestamp for it as was driving while listening a month or so ago. I do recall both talked about how their max HR had dropped off & Mike said his was never that high. Age appears to be the answer. [peterattiamd.com] Also they talk about how exercise performance drops off dramatically in the mid 70's.

Your performance seems to still be doing very well!

One never wants to see performance drop, but there is no way around it other than doing everything possible to slow it down.

Two things put me into O2 debt pretty fast. Goblet squats,3 sets of 20. And interval swimming. It's hard for me to ignore maximum swim stroke efficiency, which is the result of my swimming and coaching history, and it keeps me from just swimming slowly.

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GeorgeN
[peterattiamd.com]

Thanks for that link. 2+ hrs discussion. Only had time fore the first 40min, but something clicked in me regarding the importance of structured exercise as opposed to lifestyle exercise. So it's potentially a life-changing video for me. Thanks. They also mention how the hazard ratio for exercise is a magnitude greater than all other factors such as sleep, nutrition,.... Speaking critically, though, they are in each other's bubble. So no debate / critique / etc. Maybe it comes in later.

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Ken
swimming

Is it mostly pool swimming? any open water?

Pool swimming only

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Kwilk
[peterattiamd.com]

Thanks for that link. 2+ hrs discussion. Only had time fore the first 40min, but something clicked in me regarding the importance of structured exercise as opposed to lifestyle exercise. So it's potentially a life-changing video for me. Thanks. They also mention how the hazard ratio for exercise is a magnitude greater than all other factors such as sleep, nutrition,.... Speaking critically, though, they are in each other's bubble. So no debate / critique / etc. Maybe it comes in later.

Attia is certainly in the category of being pro exercise. I'm a paid subscriber, so get his "Ask Me Anything" podcasts and many are on the exercise topic. He's an interesting fellow, undergrad is Mech Engineering, MD @ Stanford and trained as a cancer surgeon at Hopkins, then an NIH fellow. After a stint as a McKinsey & Company consultant, he now has a concierge practice for very successful people focusing on longevity. The number of patients he treats is very small, so a lot attention to each person. He has a staff of 7 analysts to gather information from the research for how he treats his patients. He gives out much of this info in his podcasts, so a self-motivated non-patient can get much of the benefit. He also has a number of doctors on his staff treating patients. He also promotes sleep, nutrition and all the lifestyle stuff too. He was doing a 7 day fast once a quarter and now does a 3 day fast once a month. He's worn a CGM for a number of years. He also focuses on mental health as well.

All that being said, I think there are ways to get much of the benefit of exercise without as much time commitment as Attia advocates. I'm also one who pushes also all the lifestyle buttons (sleep, nutrition, as well as certain small molecules & etc.). I happen to have a genetic risk for Alzheimer's disease, so, for me, afib is just a sideshow. One of my childhood friends ended up with afib a couple of years ago and I offered to coach him. He declined, saying that I have a "six-sigma lifestyle" and he has no interest (though he "runs," he's also very materially overweight).

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GeorgeN

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kwilk

Attia is certainly in the category of being pro exercise. I'm a paid subscriber, so get his "Ask Me Anything" podcasts and many are on the exercise topic. He's an interesting fellow, undergrad is Mech Engineering, MD @ Stanford and trained as a cancer surgeon at Hopkins, then an NIH fellow. After a stint as a McKinsey & Company consultant, he now has a concierge practice for very successful people focusing on longevity. The number of patients he treats is very small, so a lot attention to each person. He has a staff of 7 analysts to gather information from the research for how he treats his patients. He gives out much of this info in his podcasts, so a self-motivated non-patient can get much of the benefit. He also has a number of doctors on his staff treating patients. He also promotes sleep, nutrition and all the lifestyle stuff too. He was doing a 7 day fast once a quarter and now does a 3 day fast once a month. He's worn a CGM for a number of years. He also focuses on mental health as well.

All that being said, I think there are ways to get much of the benefit of exercise without as much time commitment as Attia advocates. I'm also one who pushes also all the lifestyle buttons (sleep, nutrition, as well as certain small molecules & etc.).

We watched another half hour last night. Attia and Joyner are definitely in each others bubble, so debate is still lacking. They are continuing to bring up lots of fascinating study-results, and we're learning alot, for example the concept of MET-Hours per week, how MET and VO2Max are related, and some basic ideas of METs requirements of activity X, for example a 10-minute mile is 10 MET effort (I presume on the flats). We're still psyched up by the, errrr, infomercial, and will incorporate some of the ideas, probably track our MET-hours/week, add in some structured exercise and some high-intensity exercise by, for example, adding in some high-HR intervals to our otherwise casual hiking. We're not likely to 7-10 hours per week of structured exercise though.

Anyway, we still haven't heard Attia and Joyner talk about a kind of study that would be foundational for their business: Choose one or another centennial-decathlon, find a large study sample that has attained it, then run some statistical analyses like ICA on a slew of personal-habit/lifestyle parameters. We have our suspicions of the outcome. There are some other limitations that are not addressed, at least not yet. The study result that we're really interested in is not the increase in longevity of 3-5 years, but the increase in health-span by 6-8 years. And for that, Attia and Joyner's recipe is to protect against age-related decline in VO2Max. And we're on board with that, to the extent we understand it. Great podcast. Thanks again.

Back onto the original topic, here is a 2022 paper with 18 authors from ~18 institutes in 6 countries.

Abstract: Effect of MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation: The DECAAF II Randomized Clinical Trial

Some of you (@susan.d in particular) may remember it being discussed 3 months ago in regards to question of how aggressively/conservatively should ablations be carried out. The thread is: Simple ablation is the best..

The tread was based on a medicalexpress dot com post, which was really just a repost of a news release by Tulane University.

Like any science-journalism, if you want to understand you have to cut out the middle man (journalist) and read the actual paper. And if you want to really understand the paper, you need to talk to the people that actually did the work, not the PI. So much gets lost in translation. I haven't done the later, but I did do the former and it's clear there are some misinformed/incorrect statements in in that thread.

Here is the paper: Effect of MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation: The DECAAF II Randomized Clinical Trial

To perhaps clear things up, here are some snippets from the paper:

investigator-initiated, multicenter, randomized clinical trial involving 44 academic and nonacademic centers in 10 countries. A total of 843 patients with symptomatic or asymptomatic persistent AF and undergoing AF ablation were enrolled from July 2016 to January 2020, with follow-up through February 19, 2021.

Patients with persistent AF were randomly assigned to pulmonary vein isolation (PVI) plus MRI-guided atrial fibrosis ablation (421 patients) or PVI alone (422 patients).

There was no significant difference in atrial arrhythmia recurrence between groups (fibrosis-guided ablation plus PVI patients, 175 [43.0%] vs PVI-only patients, 188 [46.1%] ......

So what they found was that MRI+PVI didn't improve the outcomes, even when compared to PVI-only ablations (which at 46% recurrence leaves lots of room for improvement). Moreover, they found that MRI+PVI was more dangerous than PVI-only.

The paper's conclusion is merely, "Findings do not support the use of MRI-guided fibrosis ablation for the treatment of persistent AF."

My reading is that the paper debunked something that was being pushed by tech companies. I thought the peer-reviewed study was well done, certainly not "badly flawed study" with "sweeping conclusions".

The press release was hyped and perhaps inaccurate, as news seems to be these days.

Nice find, but my reading would be that simply targeting fibrosis for ablation is a misguided approach. Yes, fibrosis is probably key to the underlying disease, but simply ablating all the fibrotic tissue is a shotgun approach. Just because it's fibrotic doesn't mean it's a source of afib. Any approach that involves destroying tissue probably needs to be very specific and targeted at only that tissue that's causing the problem.

I'm not sure I understand. Are you saying something different than "Findings do not support the use of MRI-guided fibrosis ablation for the treatment of persistent AF."

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Kwilk
I'm not sure I understand. Are you saying something different than "Findings do not support the use of MRI-guided fibrosis ablation for the treatment of persistent AF."

I'll try. Carey is not saying something different. How about this. Afib likely has fibrotic tissue as an underlying cause. However all fibrotic tissue does not cause afib. Hence ablating all the fibrotic tissue would ablate much more tissue than is necessary. Therefore doing what many EPs do, which is to ablate tissue that is actually shown to be initiating afib, using observations done during the ablation makes much more sense.

For example, the isoproterenol challenge after the PVAI phase of an ablation.

Yep, thank you for clarifying what I meant.

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GeorgeN
Hence ablating all the fibrotic tissue

All? Where does that come from?

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Kwilk

Hence ablating all the fibrotic tissue

All? Where does that come from?

"After PVI and PV entrance block have been confirmed, fibrosis guided ablation ensued. The operator encircled by ablating at the perimeter of the fibrosis, and/or completely covered all fibrotic areas with ablation lesions, and ensured loss of capture in the fibrotic isolated area at 10 mA stimulation. The tagged ablation lesions should confirm encircling and/or covering of the entire contiguous fibrotic areas indicated by the mapping system. Ablation to the fibrotic areas were performed as per the operator's standard point lesion energy delivery strategy. "

Source: Efficacy of LGE MRI guided fibrosis ablation versus conventional catheter ablation of atrial fibrillation: The DECAAF II trial: Study design

Comment, the effort you are expending to find the best procedure may be better spent on selecting the best ablating EP and let them choose the best procedure, in my opinion. My pick is Andrea Natale.

"Following PVI using cryoballoon ablation, the use of focal cryo-balloon or radiofrequency ablation of fibrotic areas was left to the discretion of the operator. In case of cryoballoon ablation, further ablation to cover areas of atrial fibrosis should be guided by 3D Mapping system, intracardiac echocardiography, or fluoroscopic landmarks. The duration of freezing targeting fibrotic areas was left to the discretion of the operator."

Same source.

[en.wikipedia.org]

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GeorgeN
My pick is Andrea Natale.

What other EP's have been recommended by forum members?

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Kwilk
What other EP's have been recommended by forum members?

Many, but where are you asking about?

lower 48 states

That doesn't change the answer because I don't think I've ever heard of an EP in Alaska or Hawaii being discussed here.

If you're good with anyone in the lower 48, why not choose the best there is? People usually only want to limit the choices to keep it local or at least limit distance. So if you at least named a geographic area like the west coast or east coast or south or whatever, it would be a more answerable question.

To avoid further derailment of this thread, I have forked the national EP subject to a new thread.

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web
... it is still uncertain which ablation approach is the most effective. Whether to ablate the “triggers” that initiate AF or the “substrate” that supports it.

researchgate.com: Non-Invasive Identification of Atrial Fibrillation Driver Location Using the 12-lead ECG: Pulmonary Vein Rotors vs. other Locations

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web
Recently, Narayan et al. developed a computational mapping technique capable of identifying AF localized sources that may correspond to organized reentrant circuits (i.e., rotors) or focal impulses that have been reported in animal models of AF.50 The benefit of ablation of these localized sources—called Focal Impulses and Rotor Modulation (FIRM) ablation—has been tested against conventional ablation in a multicenter observational study including 92 patients with predominantly persistent AF (72%).51 Localized rotors or focal impulses were found in 97% of cases, and ablation of these sites resulted in AF termination or consistent slowing in 86%. After a median follow-up of 273 days, patients who underwent FIRM ablation had higher freedom from recurrent AF compared to conventional ablation (single procedure success: 82.4% vs. 44.9%, P < 0.001). Overall, the results reported by Narayan et al. are promising ....

Authors Santangeli and Lin (Santangeli being a Natale mentee according to another forum member)
nih.gov: Catheter Ablation of Paroxysmal Atrial Fibrillation