European Heart Journal Advance Access published online on July 2, 2008
European Heart Journal, doi:10.1093/eurheartj/ehn300
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How to assess the efficacy of catheter ablation of atrial fibrillation?
Institute of Cardiology
University of Bologna
S. Orsola-Malpighi Hospital
Via Massarenti, 9
Bologna 40139
Italy
Tel: +39 05 134 9858
Fax: +39 05 134 4859
Email: cristian.martignani{at}gmail.com
Institute of Cardiology
University of Bologna
S. Orsola-Malpighi Hospital
Via Massarenti, 9
Bologna 40139
Italy
Institute of Cardiology
University of Bologna
S. Orsola-Malpighi Hospital
Via Massarenti, 9
Bologna 40139
Italy
Institute of Cardiology
University of Bologna
S. Orsola-Malpighi Hospital
Via Massarenti, 9
Bologna 40139
Italy
Institute of Cardiology
University of Bologna
S. Orsola-Malpighi Hospital
Via Massarenti, 9
Bologna 40139
Italy
Institute of Cardiology
University of Bologna
S. Orsola-Malpighi Hospital
Via Massarenti, 9
Bologna 40139
Italy
Catheter ablation is an expanding treatment for atrial fibrillation (AF). But, the real outcome in terms of AF burden in the middle–long term after catheter ablation is still under evaluation. Most of the studies report a success rate for paroxysmal AF (PAF) between 60 and 80%,1 even if recent observations showed that this procedure does not eliminate PAF in up to 56% of patients over an extended (>3 years) follow-up period, despite the use of two or three ablation procedures in two-thirds of them.2
In their work, Steven et al.3 focused on AF burden after catheter ablation in a highly selected cohort of pacemaker and implantable cardioverter defibrillator carriers.
The analysis of the atrial electrograms recorded by their devices was used as an index of success of AF ablation in terms of relapses either for persistent AF (PersAF) or PAF, using the following device settings: (i) arrhythmia duration: >30 s, (ii) atrial frequency: <330 ms, and (iii) atrial sensitivity: 0.5 mV. According to their evaluation, AF burden dropped remarkably both for patients with PAF and with PersAF after catheter ablation.
Anyway, some observations are needed: first of all, the electrogram-storage capabilities of devices are limited in terms of number/duration of arrhythmic episodes and some episodes may be lost between the follow-up visits. Secondly, according to Israel and Barold,4 since AF diagnosis needs a 12-surface-lead ECG or multiple intracardiac recordings, device-detected atrial tachyarrhythmias should not be labelled AF even if device criteria are satisfied. Moreover, if we relay on the maximum detected atrial rate of >180 b.p.m., coupled with a high-atrial sensitivity (0.5 mV) (as used by Steven et al.), we could be in a condition in which AF, atrial flutter, or atrial/sinus tachycardia may overlap.
These remarks, in our opinion, are important in consideration of the possible clinical implication of Steven et al.'s paper.
Since AF is the most common sustained arrhythmia in the western world, showing an increasing incidence (primarily due to ageing of the population), it triggers a heavy financial burden for our health care systems,5–8 related to morbidity, hospitalizations, and mortality.
Since it has not yet been proved that catheter ablation's outcomes are definitely superior than medical therapy in terms of hard end-points, and considering that economic advantages of catheter ablation with respect to medical therapy of AF emerge only after 5 years,9 it appears reasonable to restrict the candidates to AF ablation only to selected patients at higher chance of long-term maintenance of sinus rhythm. In view of these considerations, the definition of reliable indexes of successful catheter ablation of AF at long term remains to be assessed.
References
- Haissaguerre M, Jais P, Shah DC, Takahashi A, Hocini M, Quiniou G, Garrigue S, Le Mouroux A, Le Metayer P, Clementy J. Spontaneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary veins. N Engl J Med (1998) 339:659–666.
[Abstract/Free Full Text] - Katritsis D, Wood MA, Giazitzoglou E, Shepard RK, Kourlaba G, Ellenbogen KA. Long-term follow-up after radiofrequency catheter ablation for atrial fibrillation. Europace (2008) 10:419–424.
[Abstract/Free Full Text] - Steven D, Rostock T, Lutomsky B, Klemm H, Servatius H, Drewitz I, Friedrichs K, Ventura R, Meinertz T, Willems S. What is the real atrial fibrillation burden after catheter ablation of atrial fibrillation? A prospective rhythm analysis in pacemaker patients with continuous atrial monitoring. Eur Heart J (2008) 29:1037–1042.
[Abstract/Free Full Text] - Israel CW, Barold SS. Can implantable devices detect and pace-terminate atrial fibrillation? Pacing Clin Electrophysiol (2003) 26:1923–1925.[CrossRef][Medline]
- Boriani G, Diemberger I, Martignani C, Biffi M, Branzi A. The epidemiological burden of atrial fibrillation: a challenge for clinicians and health care systems. Eur Heart J (2006) 27:893–894.
[Free Full Text] - Go AS, Hylek EM, Phillips KA, Chang Y, Henault LE, Selby JV, Singer DE. Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study. J Amer Med Assoc (2001) 285:2370–2375.
[Abstract/Free Full Text] - Wattigney WA, Mensah GA, Croft JB. Increasing trends in hospitalization for atrial fibrillation in the United States, 1985 through 1999: implications for primary prevention. Circulation (2003) 108:711–716.
[Abstract/Free Full Text] - Le Heuzey JY, Paziaud O, Piot O, Said MA, Copie X, Lavergne T, Guize L. Cost of care distribution in atrial fibrillation patients: the COCAF study. Am Heart J (2004) 147:121–126.[CrossRef][Web of Science][Medline]
- Khaykin Y. Cost-effectiveness of catheter ablation for atrial fibrillation. Curr Opin Cardiol (2007) 22:11–17.[Web of Science][Medline]
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