To the Editor: In their study of circumferential pulmonary-veinablation in patients with chronic atrial fibrillation, Oralet al. (March 2 issue)1 do not mention evaluation or discussthe potential complication of pulmonary-vein stenosis. In theirdefinition of ostial stenosis, they rely on the electroanatomical"tube depiction" method as a guide; this is a suboptimal methodfor exact ostial demarcation since the tubes are automaticallycentralized around the acquired points. Any movement by thepatient can also make electroanatomical mapping even more inaccurate.
Although the authors report no follow-up for the assessmentof pulmonary-vein stenosis, a recent study involving magneticresonance imaging detected a variable degree of stenosis in38 percent of pulmonary veins ablated with the use of the electroanatomicalapproach.2 A recent worldwide survey has shown that pulmonary-veinstenosis occurs in about 1.3 percent of patients.3 In addition,the authors mention that a patient died of pneumonia after ablation.However, they give no details about any further diagnostic investigation.Many reports, including one by Salamon et al.4 in the same issueof the Journal, have emphasized that pulmonary-vein stenosisis associated with symptoms that may mimic common lung diseases,which can lead to unnecessary diagnostic and therapeutic procedures.5
Oussama Musbah Wazni, M.D. Tamer S. Fahmy, M.D. Andrea Natale, M.D. Cleveland Clinic Foundation Cleveland, OH 44195
References
Oral H, Pappone C, Chugh A, et al. Circumferential pulmonary-vein ablation for chronic atrial fibrillation. N Engl J Med 2006;354:934-941. [Free Full Text]
Dong J, Vasamreddy CR, Jayam V, et al. Incidence and predictors of pulmonary vein stenosis following catheter ablation of atrial fibrillation using the anatomic pulmonary vein ablation approach: results from paired magnetic resonance imaging. J Cardiovasc Electrophysiol 2005;16:845-852. [CrossRef][Web of Science][Medline]
Cappato R, Calkins H, Chen SA, et al. Worldwide survey on the methods, efficacy, and safety of catheter ablation for human atrial fibrillation. Circulation 2005;111:1100-1105. [Free Full Text]
Salamon F, Hirsch R, Tur-Kaspa R, Kramer MR. Search for the complication. N Engl J Med 2006;354:957-963. [Free Full Text]
Saad EB, Marrouche NF, Saad CP, et al. Pulmonary vein stenosis after catheter ablation of atrial fibrillation: emergence of a new clinical syndrome. Ann Intern Med 2003;138:634-638. [Free Full Text]
To the Editor: Oral et al. report that "there were no complications"in a trial of catheter ablation for atrial fibrillation. Thisconclusion lacks meaning without consideration of the limitedpower of the study to detect rare but clinically significantevents. The incidence of atrioesophageal fistula associatedwith this procedure has been estimated at less than 1 percent.1Even if the incidence were as high as 2 percent, the study byOral et al. had less than 5 percent power to detect such a difference.Moreover, the authors followed patients for only 12 months afterthe procedure — a period that may be insufficient forthe detection of occurrences of pulmonary-vein stenosis.2
The determination of the efficacy of a treatment with the useof a superiority design does not allow investigators to concludethat rates of adverse events are equivalent.3 Guidelines forthe reporting of adverse events have been proposed that emphasizethe need to discuss the limited power of trials to detect rareoccurrences.4 This generally relevant consideration5 takes onincreased importance when an adverse event is already recognizedand potentially catastrophic.1
Scott K. Aberegg, M.D., M.P.H. Ohio State University College of Medicine and Public Health Columbus, OH 43210 scottaberegg{at}hotmail.com
David Majure, M.D., M.P.H. Johns Hopkins School of Medicine Baltimore, MD 21205
References
Doll N, Borger MA, Fabricius A, et al. Esophageal perforation during left atrial radiofrequency ablation: is the risk too high? J Thorac Cardiovasc Surg 2003;125:836-842. [Free Full Text]
Arentz T, Jander N, von Rosenthal J, et al. Incidence of pulmonary vein stenosis 2 years after radiofrequency catheter ablation of refractory atrial fibrillation. Eur Heart J 2003;24:963-969. [Free Full Text]
Piaggio G, Elbourne DR, Altman DG, Pocock SJ, Evans SJW. Reporting of noninferiority and equivalence randomized trials: an extension of the CONSORT Statement. JAMA 2006;295:1152-1160. [Free Full Text]
Ioannidis JPA, Evans SJW, Gotzsche PC, et al. Better reporting of harms in randomized trials: an extension of the CONSORT statement. Ann Intern Med 2004;141:781-788. [Free Full Text]
Bresalier RS, Sandler RS, Quan H, et al. Cardiovascular events associated with rofecoxib in a colorectal adenoma chemoprevention trial. N Engl J Med 2005;352:1092-1102. [Free Full Text]
To the Editor: In the study by Oral et al., the mean age ofpatients who were randomly assigned to undergo pulmonary-veinablation was 55 years, and about 92 percent of them did nothave structural heart disease. The study population was highlyselected and was not representative of the general populationof patients with chronic atrial fibrillation.1 Thus, it is prematureto conclude that sinus rhythm can be maintained in the longterm in the majority of patients with chronic atrial fibrillationby means of pulmonary-vein ablation. Such a conclusion can bemisleading, considering that most patients with chronic atrialfibrillation are elderly and that thromboembolism is one ofthe leading causes of complications and death associated withatrial fibrillation.1
The results of the Atrial Fibrillation Follow-up Investigationof Rhythm Management (AFFIRM) trial2 should be applied to themajority of patients with chronic atrial fibrillation, and appropriateantithrombotic strategies should not be replaced by attemptsto maintain sinus rhythm by catheter ablation. On the basisof currently available data, highly selected younger patientswhose condition is refractory to medical treatment and who donot have structural heart disease3 may be most likely to benefitfrom catheter ablation for paroxysmal or chronic atrial fibrillation.
Johann Auer, M.D. Gudrun Lamm, M.D. Bernd Eber, M.D. General Hospital Wels A-4600 Wels, Austria johann.auer{at}klinikum-wels.at
References
Fuster V, Ryden LE, Asinger RW, et al. ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients with Atrial Fibrillation) developed in collaboration with the North American Society of Pacing and Electrophysiology. Circulation 2001;104:2118-2150. [Free Full Text]
The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Investigators. A comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med 2002;347:1825-1833. [Free Full Text]
Wazni OM, Marrouche NF, Martin DO, et al. Radiofrequency ablation vs antiarrhythmic drugs as first-line treatment of symptomatic atrial fibrillation: a randomized trial. JAMA 2005;293:2634-2640. [Free Full Text]
The authors reply: The risk of pulmonary-vein stenosis dependson the ablation technique, energy source, maximum power andtemperature, and whether energy was delivered within pulmonaryveins. Circumferential pulmonary-vein ablation is performedoutside the pulmonary veins. A previous study demonstrated thatthe procedure was not associated with any significant pulmonary-veinstenosis.1 However, we do understand the concern of Wazni etal. regarding pulmonary-vein stenosis.2 In the study by Donget al.,3 unlike this study, linear lesions were created betweenthe ipsilateral superior and inferior pulmonary veins, whichincreased the risk of stenosis. Dong et al. reported in thesame study that stenosis occurred only when this line was created.The worldwide survey included patients from 100 centers thatused a variety of techniques between 1995 and 2002. Therefore,these findings may not be representative of current practice,particularly when the rapid evolution of ablation strategiesand techniques is considered. In our study, the 66-year-oldman who died had a fatal case of Stenotrophomonas maltophiliapneumonia after surgical intervention for an aortic aneurysmseven months after the ablation.
Aberegg and Majure point out that our study did not have sufficientpower to assess safety. However, as indicated, the primary endpoint was efficacy. Because the incidence of atrioesophagealfistula is very low, more than 1700 patients would be requiredin each group for a study to detect a difference at a powerof 0.90. Because atrioesophageal fistula is a rare but oftenfatal complication, it was discussed in detail. Nevertheless,large-scale multicenter trials with an extended duration willbe necessary to determine the ultimate safety of ablation inthe treatment of atrial fibrillation. However, because ablationstrategies are still evolving, such trials may not be feasiblein the near future.
We agree with Auer et al. that the study population was notrepresentative of all patients with chronic atrial fibrillation.However, we strongly disagree that the AFFIRM results shouldbe applied to the majority of patients with atrial fibrillation.As discussed, there are important differences between the subjectsof the AFFIRM trial and those in our study, since patients inthe AFFIRM study were older (mean [±SD] age, 70±9),had at least one risk factor for stroke, and were unlikely tohave debilitating symptoms caused by the atrial fibrillation.Furthermore, sinus rhythm was maintained in only one third ofthe rhythm-control group. We believe that our study has demonstratedthat catheter ablation is a reasonable option for younger patientswhose quality of life is disturbed by chronic atrial fibrillationand whose condition has not responded well to drug therapy orcardioversion.
Hakan Oral, M.D. University of Michigan Ann Arbor, MI 48109 oralh{at}umich.edu
Carlo Pappone, M.D. San Raffaele University Hospital 20132 Milan, Italy
Fred Morady, M.D. University of Michigan Ann Arbor, MI 48109
References
Lemola K, Sneider M, Desjardins B, et al. Effects of left atrial ablation of atrial fibrillation on size of the left atrium and pulmonary veins. Heart Rhythm 2004;1:576-581. [CrossRef][Web of Science][Medline]
Qureshi AM, Prieto LR, Latson LA, et al. Transcatheter angioplasty for acquired pulmonary vein stenosis after radiofrequency ablation. Circulation 2003;108:1336-1342. [Free Full Text]
Dong J, Vasamreddy CR, Jayam V, et al. Incidence and predictors of pulmonary vein stenosis following catheter ablation of atrial fibrillation using the anatomic pulmonary vein ablation approach: results from paired magnetic resonance imaging. J Cardiovasc Electrophysiol 2005;16:845-852. [CrossRef][Web of Science][Medline]
The editorialists reply: In our editorial1 accompanying thestudy by Oral et al., we stated, "According to the latest guidelinesof the American Heart Association [AHA], the American Collegeof Cardiology [ACC], and the European Society of Cardiology[ESC], catheter ablation is considered standard therapy forpatients who have symptomatic paroxysmal atrial fibrillationafter having had no response to a single antiarrhythmic drug."This statement is incorrect, since the only approved guidelineson this topic are those from 2001, rather than those we citedas being currently "in press." Although a revision is underdevelopment, it has not been completed. The current policy ofthe organizations regarding this issue can be found in the 2001ACC–AHA–ESC guidelines on atrial fibrillation.2
In addition, our statement and the accompanying citation violatethe confidentiality policies of these three organizations forthe development of guidelines — policies that are specificallydesigned to prevent premature distribution of draft recommendationsthat are not yet approved, as was done in this case. We deeplyregret the inclusion of misleading information about the positionof the organizations in our editorial and our erroneous citationof the guidelines as being "in press," as well as our violationof the policies of the organizations regarding the developmentof guidelines.
Mark A. Wood, M.D. Kenneth A. Ellenbogen, M.D. Virginia Commonwealth University Medical Center Richmond, VA 23284
References
Wood MA, Ellenbogen KA. Catheter ablation of chronic atrial fibrillation -- the gap between promise and practice. N Engl J Med 2006;354:967-969. [Free Full Text]
Fuster V, Rydén LE, Asinger RW, et al. ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients with Atrial Fibrillation): developed in collaboration with the North American Society of Pacing and Electrophysiology. J Am Coll Cardiol 2001;38:1231-1266. [Free Full Text]
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