Simplifying atrial fibrillation ablation: How far can we go? Thomas Rostock, MD, Torsten Konrad, MD, Cathrin Theis, MD From the II. Medical Clinic, Department of Electrophysiology, University Medical Center, Johannes Gutenberg-University, Mainz, Germany.

The procedural end point of electrical isolation of the pulmonary veins (PVs) for the treatment of atrial fibrillation (AF) has been debated extensively. After identifying the PVs as the dominant arrhythmogenic site of paroxysmal AF,1 2 fundamentally different approaches to the interventional treatment of AF were introduced. Haissaguerre et al2 developed a technique to electrically isolate the PVs by targeting electrophysiological (EP) breakthroughs from the left atrium to the PVs guided by a circular mapping catheter. In contrast, Pappone et al3 implemented an anatomical approach that used circumferential ablation lines around the PVs guided by a 3-dimensional mapping system. This latter approach used the procedural end point of local electrogram amplitude reduction on the line and assessment of voltage maps within the encircled area but not the demonstration of PV isolation. For a considerably long time, these 2 different approaches separated the EP community in terms of AF ablation into 2 fractions according to their affinity to either of these techniques. Subsequently, 2 independent groups performed each a prospective randomized trial comparing the 2 approaches.4,5 However, these 2 studies ultimately did not clarify which one of the approaches is the more effective and therefore more appropriate technique. In contrast, the completely divergent results of the 2 studies further heated up this debate. Interestingly, although no additional clarifying data were published afterward, the 2007 Heart Rhythm Society/European Heart Rhythm Association/European Cardiac Arrhythmia Society consensus documents recommended for the first time that in AF ablation approaches targeting the PVs, complete electrical isolation should be the goal.6 With this statement, discussions on whether electrical isolation should be used as the EP end point of PV ablation abated subsequently. The contemporary approach to PV isolation consolidates the combination of both techniques, a wide circumferential linear ablation around the ipsilateral PVs with the end point of electrical isolation guided by a circular PV mapping catheter.7,8 Recently, the German Gap-AF (AFNET 1) study demonstrated Address reprint requests and correspondence: Dr Thomas Rostock, II. Medical Clinic, Department of Electrophysiology, University Medical Center, Johannes Gutenberg-University Mainz. Langenbeckstr. 1, D-55131 Mainz, Germany. E-mail address: [email protected].

1547-5271/$-see front matter B 2014 Heart Rhythm Society. All rights reserved.

in a prospective randomized multicenter trial for the first time that even with the demonstration of electrical recovery 3 months after initially completely isolating circumferential PV lines, the arrhythmia-free outcome was significantly better as compared to patients with an intentionally left residual conduction.9 In this issue of HeartRhythm, Pérez-Castellano et al10 add important new data on this topic. Fifty patients with paroxysmal AF were randomized to undergo either cryoballoon or radiofrequency (RF) ablation of the PVs. In the cryoballoon group, two 300-second freezes per PV were applied. The EP effect was determined with a PV mapping catheter, but no further ablation was performed in the case of residual electrical PV conduction. In the RF group, the end point of circumferential PV ablation was electrical isolation verified by a circular mapping catheter. All patients underwent a thorough follow-up using an implantable cardiac monitor (Reveal XT) for 12 months. The study revealed 3 key observations: (1) even 2 consecutive 300second cryoballoon applications per PV result in complete isolation of all targeted veins in only less than half of the patients; (2) a virtuously “anatomical” cryoballoon ablation is inferior to RF-mediated PV isolation confirmed by using a circular mapping catheter; (3) comparing only patients with the end point of completely isolated PVs at the end of the procedure, no difference in outcome was observed between patients treated with cryo vs RF ablation. Ultimately, these findings indicate that the procedural success depends on the EP end point and not the type of energy source. The authors are to be congratulated for a well-designed and carefully performed study. Even while keeping in mind the small sample size limitation, this study further corroborates the Heart Rhythm Society/European Heart Rhythm Association/European Cardiac Arrhythmia Society consensus statement recommending the end point of complete PV isolation. Thus, in conjunction with the results of the Gap-AF trial, an elevation from evidence level class 1c to class 1a should be considered for the end point of electrical PV isolation in future guidelines.8 Moreover, these data underscore the requirement to carefully evaluate the EP end point of PV ablation whatever technique or energy source is applied.


16 Owing to the high prevalence and increasing incidence of AF, one of the major goals of both researchers and AF ablation device manufacturers was to simplify the AF ablation procedure, permitting its broad and perhaps more general application. Even though the impetus to simplify this procedure is commendable, the crucial question is how far can we go in simplifying AF ablation per se? In Germany, a beneficial financial reimbursement for AF ablation has made this procedure an attractive medical accomplishment for health care professionals. Rumors have circulated in the German EP community that some interventional cardiologists started performing cryoballoon PV ablation for AF without any prior basic EP training and without the competence to evaluate any EP end point. Undoubtedly, the cryoballoon technique constitutes the prime example of a straightforward procedure for AF, which certainly can be performed by a dedicated interventional cardiologist. However, the article presented by PérezCastellano et al10 should alert us that even if AF ablation becomes technically more convenient, it still requires careful consideration of the EP end points to achieve the utmost outcome. Thus, simplifying AF ablation is always welcome as long as we do not take this EP procedure too simply.

Heart Rhythm, Vol 11, No 1, January 2014

References 1. Haissaguerre M, Jais P, Shah DC, et al. Spontaneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary veins. N Engl J Med 1998;339:659–666. 2. Haissaguerre M, Shah DC, Jais P, et al. Electrophysiological breakthroughs from the left atrium to the pulmonary veins. Circulation 2000;102:2463–2465. 3. Pappone C, Rosanio S, Oreto G, et al. Circumferential radiofrequency ablation of the pulmonary vein ostia: a new anatomic approach for curing atrial fibrillation. Circulation 2000;102:2619–2628. 4. Oral H, Scharf C, Chugh A, et al. Catheter ablation of paroxysmal atrial fibrillation: segmental pulmonary vein ostial ablation versus left atrial ablation. Circulation 2003;108:2355–2360. 5. Karch MR, Zrenner B, Deisenhofer I, et al. Freedom from atrial tachyarrhythmias after catheter ablation atrial fibrillation: a randomized comparison between 2 current ablation strategies. Circulation 2005;111:2875–2880. 6. Calkins H, Brugada J, Packer DL, et al. HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for personnel, policy, procedures and follow-up. Heart Rhythm 2007;6:335–379. 7. Ouyang F, Bänsch D, Ernst S, et al. Complete isolation of the left atrium surrounding the pulmonary veins: new insights from the double-Lasso technique in paroxysmal atrial fibrillation. Circulation 2004;110:2090–2096. 8. Arentz T, Weber R, Bürkle G, et al. Small versus large isolation areas around the pulmonary veins for the treatment of atrial fibrillation? Results from a prospective randomized study. Circulation 2007;115:3057–3063. 9. Kuck KH, Willems S, Breithardt G, for the Gap-AF Study Investigators. Gap-AF —AFNET-1 trial. Europace 2013;15:ii-270–ii-292. 10. Pérez-Castellano N, Fernández-Cavazos R, Moreno J, et al. The COR trial: a randomized study with continuous rhythm monitoring to compare the efficacy of cryoenergy and radiofrequency for pulmonary vein isolation. Heart Rhythm 2014;11:8–14.

Simplifying atrial fibrillation ablation: how far can we go?

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