Editor's Note: John Mandrola, MD interviews Alexander Fürnkranz, MD at the Heart Rhythm Society 2016 Scientific Sessions about recent updates in the electrophysiology world.
John M. Mandrola, MD: Hi everyone. This is John Mandrola from theheart.org on Medscape, and I'm here in San Francisco at the Heart Rhythm Society meeting. I am very excited to have my friend and mentor, Alex Fürnkranz from Frankfurt, Germany—CCB Hospital in Frankfurt. Alex is a highly published author and expert in catheter ablation of atrial fibrillation [AF] and expert in cryoablation and a second author on the FIRE and ICE trial.[1] Welcome, Alex.
Alexander Fürnkranz, MD: Thank you, John.
Dr Mandrola: It is great to have you. Let's talk first about FIRE and ICE. Give us the background and then we will go into methods, results, and discussion.
FIRE and ICE Trial Design
Dr Fürnkranz: Well, at the time we designed the study, in 2011–2012,[2] there were two major technologies available to perform pulmonary-vein isolation [PVI] to treat atrial fibrillation, and by far the dominating one was radiofrequency current [RFC] ablation, typically performed with a 3D mapping system. The other, emerging, technique was the cryoballoon technique.
For both techniques, trials [had shown] superiority with respect to antiarrhythmic drug therapy,[3,4] but what was lacking was a direct head-to-head comparison between those two techniques. FIRE and ICE was designed as a parallel-group noninferiority trial to compare efficacy and safety of these two techniques to perform pulmonary-vein isolation.
Dr Mandrola: So it is a randomized controlled trial of the two?
Dr Fürnkranz: Exactly.
Dr Mandrola: And how many centers?
Dr Fürnkranz: There were 16 centers involved in eight European countries.
Dr Fürnkranz: Tell us about the patients who were randomized.
Dr Fürnkranz: These were patients with paroxysmal atrial fibrillation (PAF) aged 18 to 70 years, and they failed antiarrhythmic drug treatment either with a membrane-active antiarrhythmic drug or with a beta-blocker.
Dr Mandrola: How did it come out? Give us the results.
FIRE and ICE Outcomes
Dr Fürnkranz: Well, both with respect to the primary end point—which was recurrent atrial tachyarrhythmia, atrial flutter, atrial fibrillation, or atrial tachycardia for more than 30 seconds after the blanking period—there was equivalency between the two techniques. So, there was noninferiority shown for the cryoballoon with respect to RFC ablation.
Dr Mandrola: So, what were the results? What were the success rates?
Dr Fürnkranz: The arrhythmia-free survival rates were 65% for the cryo arm and 64% for the RFC arm.
Dr Mandrola: Which is pretty typical of ablation.
Dr Fürnkranz: Which is pretty typical. What I think we have to say at this point is that the follow-up was very robust. We had weekly and symptomatic tele-ECG monitoring. We contacted the patient every 3 months. There were office visits after 3 and 6 months and every 6 months thereafter, including Holter ECG recordings. Of course, there were triggered visits upon symptoms also including Holter monitoring, so that was a very rigorous follow-up.
Dr Mandrola: What about adverse events in the two groups?
Dr Fürnkranz: The primary safety end point was a combination of all-cause death, all-cause stroke, or a transient ischemic attack or serious adverse events with relation to the procedure, and there was also equivalency between the two arms.
Dr Mandrola: Equivalence of the two techniques in a randomized controlled trial. We talked about this before. How do you see this informing the decision about whether one should have cryoballoon or RFC, either from the patient's perspective or the electrophysiologist's?
Learning Curve for RFC vs Cryoballoon
Dr Fürnkranz: The most important thing to mention is that it is much easier to learn cryoballoon PVI than to perform PVI with RFC and a 3D mapping system. The learning curve is much steeper with the cryoballoon.
Dr Mandrola: Give us the estimate of how many cryoballoon vs RF ablation procedures it takes to become expert.
Dr Fürnkranz: Typically to be confident with cryoballoon ablation, you need around 30 to 50 procedures.
Dr Mandrola: That's not very many.
Dr Fürnkranz: That is not very many, and you can do that basically in less than 1 year, whereas, to learn RFC ablation with a 3D mapping system typically you need 3 to 5 years in a high-volume center.
Dr Mandrola: Three to 5 years to learn RFC.
Dr Fürnkranz: Exactly.
Dr Mandrola: That takes a long time, doesn't it?
Dr Fürnkranz: It takes a long time.
Dr Mandrola: I agree. Now that we settled the issue of equivalence: How do you see the role of AF ablation when you talk to your patients with AF?
Dr Fürnkranz: I think AF ablation is an important component in the treatment of patients with symptomatic atrial fibrillation, especially in the early stages of the disease.
Dr Mandrola: Expand on what you mean by "it's a component."
The Role of Risk-Factor Modification in AF
Dr Fürnkranz: Well, from [epidemiological studies] of atrial fibrillation, we know that there are risk factors that influence the incidence of the disease such as arterial hypertension, diabetes, or obesity.[5] As you know, it has been shown that by controlling these risk factors, the incidence of atrial fibrillation will also decrease. I think risk-factor control is important in the treatment of atrial fibrillation in addition to catheter ablation.
Dr Mandrola: How do you approach, for instance, obesity? We have a huge problem of obesity in US, and I assume Germany has a problem, too. Do you first recommend patients lose weight, or is there a certain [target] weight, or how do you approach this?
Dr Fürnkranz: I see most patients that I treat with catheter ablation before we do the ablation. If obesity is a problem, then I inform these patients that it is important—maybe even before having an ablation—to control those risk factors. At the time of discussing a catheter ablation in very symptomatic patients, these patients are also very motivated to control their risk factors. At a [body mass index] BMI of 40 or even higher, usually we make an attempt to control these risk factors, and if they actually succeed and still have symptomatic atrial fibrillation, then we do a catheter ablation. Usually the combination of those two factors achieves success.
Dr Mandrola: What is your perspective of the work of the Australian group in risk-factor modification?[6] It's been critiqued because they are not randomized trials or observational trials, but your view of it?
Dr Fürnkranz: It is very important work, because when we get to the pathophysiology of atrial fibrillation and when we look at obesity, then we know that obesity causes elevated pressure in the left atrium and remodeling with enlargement of the left atrium, and I think it is difficult to treat such remodeling of the left atrium caused by elevated pressure just by pulmonary-vein isolation. The triggers are one component, but I think you have to fight atrial fibrillation from different corners, and the more components you can treat, the more successful you will be.
Left Atrial Appendage Occlusion
Dr Mandrola: I agree. Excellent. I want to get your approach on one of the hot topics at HRS, left atrial appendage occlusion, and I know the US and European experience is different. I understand that in Europe you have been doing it for a lot longer. How long exactly?
Dr Fürnkranz: More than 5 years.
Dr Mandrola: What is your approach, or your view of the ideal patient for left atrial appendage occlusion?
Dr Fürnkranz: Well, I think it is important to have a technique available for patients with a clear indication for oral anticoagulation who also have a contraindication for oral anticoagulation. I think it is it's good and important to have an alternative treatment to help these patients.
Dr Mandrola: I heard you right. You said a contraindication to warfarin. You don't think it should be, say, preferential or a first-line therapy?
Dr Fürnkranz: I think at this time we do not have enough data to justify general preference of left atrial appendage occlusion over oral anticoagulation.
Dr Mandrola: Do you think that the new oral anticoagulant (NOAC) drugs changed your view of appendage occlusion? Because some have said that the NOACs are better than warfarin.
Dr Fürnkranz: Well, I think we have to wait for the results of ongoing trials comparing left atrial appendage occlusion with novel oral anticoagulants.
Dr Mandrola: Okay. I think that's it, Alex. Thank you for being with us. It's great to have you.
Dr Fürnkranz: You are very welcome.
Dr Mandrola: So that's it. This is John Mandrola from theheart.org on Medscape. Thanks for watching.
Disclosures: Alexander Fürnkranz, MD, has disclosed the following relevant financial relationships: Served as a director, officer, partner, employee, advisor, consultant, or trustee for: Medtronic.
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Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: John M. Mandrola. FIRE and ICE and Other Atrial Fib Insights - Medscape - Jun 15, 2016.
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