The Crying Game - is cryoablation worth crying about?

[www.nejm.org]

Background

Atrial fibrillation is a chronic, progressive disorder, and persistent forms of atrial fibrillation are associated with increased risks of thromboembolism and heart failure. Catheter ablation as initial therapy may modify the pathogenic mechanism of atrial fibrillation and alter progression to persistent atrial fibrillation.

Methods

We report the 3-year follow-up of patients with paroxysmal, untreated atrial fibrillation who were enrolled in a trial in which they had been randomly assigned to undergo initial rhythm-control therapy with cryoballoon ablation or to receive antiarrhythmic drug therapy. All the patients had implantable loop recorders placed at the time of trial entry, and evaluation was conducted by means of downloaded daily recordings and in-person visits every 6 months. Data regarding the first episode of persistent atrial fibrillation (lasting ≥7 days or lasting 48 hours to 7 days but requiring cardioversion for termination), recurrent atrial tachyarrhythmia (defined as atrial fibrillation, flutter, or tachycardia lasting ≥30 seconds), the burden of atrial fibrillation (percentage of time in atrial fibrillation), quality-of-life metrics, health care utilization, and safety were collected.

Results

A total of 303 patients were enrolled, with 154 patients assigned to undergo initial rhythm-control therapy with cryoballoon ablation and 149 assigned to receive antiarrhythmic drug therapy. Over 36 months of follow-up, 3 patients (1.9%) in the ablation group had an episode of persistent atrial fibrillation, as compared with 11 patients (7.4%) in the antiarrhythmic drug group (hazard ratio, 0.25; 95% confidence interval [CI], 0.09 to 0.70). Recurrent atrial tachyarrhythmia occurred in 87 patients in the ablation group (56.5%) and in 115 in the antiarrhythmic drug group (77.2%) (hazard ratio, 0.51; 95% CI, 0.38 to 0.67). The median percentage of time in atrial fibrillation was 0.00% (interquartile range, 0.00 to 0.12) in the ablation group and 0.24% (interquartile range, 0.01 to 0.94) in the antiarrhythmic drug group. At 3 years, 8 patients (5.2%) in the ablation group and 25 (16.8%) in the antiarrhythmic drug group had been hospitalized (relative risk, 0.31; 95% CI, 0.14 to 0.66). Serious adverse events occurred in 7 patients (4.5%) in the ablation group and in 15 (10.1%) in the antiarrhythmic drug group.

Conclusions

Initial treatment of paroxysmal atrial fibrillation with catheter cryoballoon ablation was associated with a lower incidence of persistent atrial fibrillation or recurrent atrial tachyarrhythmia over 3 years of follow-up than initial use of antiarrhythmic drugs. (Funded by the Cardiac Arrhythmia Network of Canada and others; EARLY-AF ClinicalTrials.gov number, NCT02825979. opens in new tab.)

I think it’s safer because it doesn’t overheat one’s heart. I was told by an ep who later was fired from the trial (take that with some caution) that he would lightly freeze an area and if the Afib continued he would deep freeze. But on the other hand if he lightly froze an area and afib remained, he would quickly move to another spot and let the healthy tissue thaw-saving heart tissue by the guessing game.

It made sense the time. Not using a disqualified Ep but the logic in savings tissue. Dr. Jais, an elite EP, once wrote:
[a-fib.com]

“ In the words of Dr. Pierre Jais of the Bordeaux Group at the 2020 AF Symposium, “We have ablated too much…Those patients when they have the (Left Atrial) Appendage taken out, they have very poor residual LA (Left Atrium) function. I don’t want that to happen anymore. If we can avoid it, I think we should.” Dr. Jais later added, “Sinus rhythm is by definition superior to persistent A-Fib. But the best ablation strategy is the one that restores sinus rhythm at the least tissue cost, thereby preserving as much as possible the LA function.”

Quote
susan.d
In the words of Dr. Pierre Jais of the Bordeaux Group at the 2020 AF Symposium, “We have ablated too much…Those patients when they have the (Left Atrial) Appendage taken out, they have very poor residual LA (Left Atrium) function. I don’t want that to happen anymore. If we can avoid it, I think we should.” Dr. Jais later added, “Sinus rhythm is by definition superior to persistent A-Fib. But the best ablation strategy is the one that restores sinus rhythm at the least tissue cost, thereby preserving as much as possible the LA function.

I'd love to hear more comments on this.

Jais seems to be conflating two things: surgical removal of the LAA vs. isolation by ablation. Isolating the LAA doesn't have a significant effect on left atrial function. Only the LAA's pumping ability is affected, and that's a tiny portion of left atrial output. About 40% of the people who have an LAA isolation procedure retain sufficient LAA pumping quality that they don't need to remain on anticoagulants.

“ But the best ablation strategy is the one that restores sinus rhythm at the least tissue cost”

In general it’s better to save heart tissue. Idk but after 4-6 ablations how much tissue is left?

He was fired so his remarks maybe rubbish but I remembered the conversation. It was my first appointment at 4pm and he talked and talked until 5 and sent his nurse home, grabbed a mug of coffee and continued to discuss his technique and the value of a cyro until 6pm! I remembered the visit because I was impressed a dr would talk for hours after sending his help home.

The only benefits of cryo over RF are that it's quick and it's simple, which means inexperienced EPs can do ablations with a decent chance of success. It can only do a basic PVI, so it's not useful at all for complex cases and touch up ablations.

Quote
Carey
The only benefits of cryo over RF are that it's quick and it's simple, which means inexperienced EPs can do ablations with a decent chance of success. It can only do a basic PVI, so it's not useful at all for complex cases and touch up ablations.

Am I wrong but the pulse trials also only ablate the PVI? I know Dr N uses both methods from reading a recent post but is it true most pulse trials are limited to the PVI? Is it because the tip is bigger?

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susan.d
Am I wrong but the pulse trials also only ablate the PVI? I know Dr N uses both methods from reading a recent post but is it true most pulse trials are limited to the PVI? Is it because the tip is bigger?

My understanding is this is for the trials. Probably because it is easier to standardize for analyzing trial results.

You have a four-cylinder car that is misfiring, and a rookie mechanic thinks it's a bad spark plug. One is easy to reach so he changes it and hopes for the best as it takes great skill and time to access the other three. Maybe he got the right one or maybe there are others not sparking correctly but for the moment, things are running smoothly.

The experienced mechanic thinks it could be any or all plugs that are misfiring, so with his skill he is able to access all four plugs, finds they are all bad, so he replaces them, and the car is now running smoothly.

Which repair shop are you going to?

Good analogy, Ken.

Susan, I think George's answer is correct. They're just limiting the procedures in order to standardize the trials, comparing apples to apples and all that.

I wish hearts were like cars Ken, where you can remove all the parts and easily replace what is not working and fix without collateral damage.

Unfortunately in the process of removing that 4th ohh so difficult to reach spark plug, what happens to even the best mechanic if he unknowingly in the process nicks the coolant hose that’s in his way, which indirectly after replacing all the parts results of having his customer return for a “touchup” when the car later overheats and the nick isn’t visible to even the top tier mechanic? Overheating in your car can cause engine damage resulting in returning once again to the mechanic for a full engine rebuild.

A heart isn’t as lucky in getting car parts. Yes you can add a pacemaker if the sinus node gets heated up during an ablation, or if all else fails after having to basically return over and over back to the hospital getting more ablations and more ECVs and more unsuccessful drug drips and boluses until one runs out of options but to agree to sever the atria from the rest of the heart by getting a drastic av ablation.

Once you start tinkering in your car, it’s a wild card and so unpredictable.



Edited 1 time(s). Last edit at 12/23/2022 02:30PM by susan.d.

susan.d

For me, it was either run on 3 cylinders forever, or find a trusted mechanic to do the repairs that were needed. There is always some risk with any and all medical treatments, but we are capable of making informed choices. If I had gone for a cryo ablation on either of my two ablations, neither would have been successful. I was asked to be in a clinical trial for cryo in 2006 for my first ablation and am glad I decided not to go that route = 13 years without afib or meds.

After some time here and lurking before that - it seems there is no standard answer, no standard solution and no standard results. There are odds and statistics but anything can work, not work, or even harm further. We all fall into that bell curve.