The AFib Summit, held during the Heart Rhythm 2007 Annual Scientific Sessions, May 9-10, in Denver, Colorado, featured world-renowned experts who presented the latest in the diagnosis, management, drug therapy, outcomes, and ablation techniques for atrial fibrillation (AF).

Consensus Statement Recap:

- AF Definitions: The task force members agreed to use the definitions in the AHA/ACC/AF consensus document published in August 2006, with a few important exceptions: The term “permanent AF” is not appropriate in the context of patients undergoing ablation of AF, as it refers to a group of patients where a decision has been made not to pursue restoration of sinus rhythm by any means.2 Thus, the group agreed that the terms “permanent AF” and “chronic AF” should no longer appear in AF literature. Instead, the term “persistent AF” should be used. “Persistent AF” is defined as AF sustained beyond 7 days, or lasting less than 7 days but necessitating pharmacologic or electrical conversion. The term “longstanding persistent AF” should be used when referring to continuous AF lasting longer than one year. Indications for Catheter Ablation: Task force members agreed that the main indication for catheter ablation is symptomatic AF refractory or intolerant to at least one Class 1 or 3 antiarrhythmic medication. They added that in rare clinical situations, performing AF ablation as first-line therapy may be appropriate. Another reasonable indication is selected symptomatic patients with heart failure and/or reduced ejection fraction. Task force members also agreed that the presence of a left atrial thrombus is a contraindication to catheter ablation of AF. Indications for Surgical Ablation: The group agreed that candidates for surgical ablation include: • Symptomatic AF patients undergoing other cardiac surgery. • Selected asymptomatic AF patients undergoing cardiac surgery in which the ablation can be performed with minimal risk. • Patients who prefer a surgical approach, who have failed one or more attempts at catheter ablation, or who are not candidates for catheter ablation. AF Ablation Techniques: Task force members agreed on the following: Ablation strategies that target the pulmonary veins (PVs) and/or PV antrum are the cornerstone for most AF ablation procedures. If the PVs are targeted, complete electrical isolation should be the goal. For surgical PV isolation, entrance and/or exit block should be demonstrated. Finally, careful identification of the PV ostia is mandatory to avoid ablation within the PVs. They also concluded that ablation of the cavotricuspid isthmus is recommended only in patients with a history of typical atrial flutter or indicible cavotricuspid isthmus dependent atrial flutter. In addition, for patients with longstanding persistent AF, ostial PV isolation alone may not be sufficient. “It is clear that we don’t know which of the many techniques discussed at this Summit is the right adjunctive technique, but this speaks to the point that you may need to do more than simply isolate the veins. Whether that’s a first or second procedure is a matter of the operator’s preference,” said Dr. Calkins. “The document does not state which technique or technology may be better because there are no good comparative studies.” Pre-Procedure Management and Intraprocedure Anticoagulation: The consensus was that anticoagulation guidelines, published in the ACC/AHA/ESC 2006 Guidelines for the Management of Patients With AF,2 should be followed for long-term management of AF ablation patients as well as for patients undergoing cardioversion procedures. The task force members also agreed that patients with persistent AF who are in AF at the time of ablation should have a transesophageal echocardiogram performed to screen for thrombus. Lastly, heparin should be administered during AF ablation procedures to achieve and maintain an activated clotting time of 300 to 400 seconds. Post-Procedure Management: The consensus was that low molecular weight heparin or intravenous heparin should be used as a bridge to the resumption of systemic anticoagulation following AF ablation. Also, Coumadin is recommended for all patients for at least 2 months following an AF ablation procedure. Decisions regarding the use of Coumadin more than 2 months following an ablation procedure should be based on the patient’s risk factors for stroke and not on the presence or type of AF. Lastly, the discontinuation of warfarin therapy post-ablation is generally not recommended in patients who have a CHADS score of 2 or greater. Training Requirements and Competencies: “The document gives a detailed description of training that is needed to perform this procedure safely and with high quality,” explained Dr. Calkins. The ACC/AHA 2006 update of the clinical competence statement on catheter ablation proposed a minimum of 30–50 AF ablation procedures for those who undergo fellowships in clinical cardiac EP.3 “We felt that this number underestimates the experience required for a high degree of proficiency, and that exact numerical values are difficult to specify because technical skills develop at different rates.” Comparisons at high- and low-volume centers show that outcomes are better at centers that have performed more than 100 procedures. Also, trainees who intend to independently perform AF ablation should consider additional training after the standard fellowship is completed. Electrophysiologists who have already completed a fellowship and undergone training for AF ablation should observe experienced colleagues and be supervised when they begin to routinely perform these procedures. In the absence of definitive data, numerical requirements are arbitrary. The exact number may depend on prior experience with transseptal punctures and cannulation of the left atrium. EPs should perform several ablation procedures for AF per month if they intend to remain active in this area. Finally, they should track the outcomes of their procedures and verify that appropriate follow-up has been arranged. Follow-up and Clinical Trial Considerations: Task force members agreed on the following definitions of success: • A three-month blanking period should be employed after ablation when reporting outcomes. • Freedom from AF/flutter/tachycardia off antiarrhythmic therapy is the primary endpoint of AF ablation. • For research purposes, time to recurrence of AF following ablation is an acceptable endpoint after AF ablation, but may underrepresent true benefit. • Freedom from AF at various points following ablation may be a better marker of true benefit and should be considered as a secondary endpoint of ablation. • Episodes of atrial flutter and other atrial tachyarrhythmias should be considered as treatment failures when they occur post ablation. • An episode of AF/flutter/tachycardia detected by monitoring should be considered a recurrence if it has a duration of 30 seconds or more. • Single procedure success should be reported in all AF catheter ablation trials. Minimal Monitoring: With regard to minimal monitoring, the group came to consensus on the following: • Patients should schedule a routine follow-up at a minimum of three months following the ablation procedure and then every six months for at least two years. • An event monitor should be obtained to screen for recurrent AF/flutter/tachycardia in patients who complain of palpitations during follow-up. • An AF/flutter/tachycardia episode is present if it is documented by ECG and lasts at least 30 seconds. • All patients participating in a clinical trial should have their progress tracked for a minimum of twelve months. • Patients being evaluated as part of a clinical trial, or in whom Coumadin may be discontinued, should have some type of continuous ECG monitoring performed to screen for asymptomatic AF/flutter/tachycardia. • 24-hour Holter monitoring is an acceptable minimal monitoring strategy for patients enrolled in a clinical trial, and is recommended at three- to six-month intervals for one to two years following ablation. Repeat Procedures and Complications: Repeat procedures should be delayed for at least three months following initial ablation, if the patient’s symptoms can be controlled with medical therapy. Dr. Calkins, when discussing complication rates, stressed that “the literature has disparate results, as most studies never define what they mean by complications.” The standard definition of a major complication, which should be included in clinical trial conclusions, is a situation that results in permanent injury or death, requires intervention for treatment, or requires hospitalization.

       Sessions during the AFib Summit covered the following topics: AF mechanisms; clinical outcomes of AF ablation; new generation imaging for ablative interventions; facilitating good outcomes and avoiding bad ones; anti-thrombotic, anti-arrhythmic, and anti-inflammatory drug therapy for AF; how to perform ablative intervention; special considerations for non-pharmacologic therapies; and the means by which to pull it all together.
       A highlight of the AFib Summit was the release of a revised consensus statement on atrial fibrillation. In this article, the central components of the HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation are described as well as how the incorporation of the statement’s guidelines will impact treatment of atrial fibrillation in the future.
       The AFib Summit featured a special presentation that summarized the newly released consensus statement on ablation of AF, which was followed by an interactive panel discussion with the experts in AF. In this article, we will summarize both the consensus statement and the panel discussion.

Summary of the Presentation on “The Heart Rhythm Society/Expert Consensus Statement on AFib Ablation: What Do We Know, What Should We Do?”
       Hugh Calkins, MD, co-chair of the AFib Summit, described the HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation as a state-of-the-art review of the field of catheter and surgical ablation of AF. The consensus statement reports the findings of a Heart Rhythm Society (HRS) task force charged with defining the indications, techniques, and outcomes of these procedures.
The statement was written in joint partnership with the European Heart Rhythm Association (EHRA) and European Cardiac Arrhythmia Society (ECAS) and endorsed by the American Heart Association, American College of Cardiology, and Society of Thoracic Surgeons. The statement was released electronically just prior to Heart Rhythm 2007, and was published in the HRS and EHRA journals in June 2007.¹
       The consensus statement summarizes the opinions of 27 task force members, who have been recognized as the world’s most prominent leaders in the field of electrophysiology (EP). Task force members received a survey and responded based on their own experiences in treating patients. Aspects of AF ablation that represented a true “consensus” were identified and described in the document, which also includes a review of the literature.
       Dr. Calkins stated that the statement has been well received by the community of electrophysiologists who care for patients with atrial fibrillation and/or perform catheter ablation procedures. From a clinical perspective this document has been well received for several reasons.
       First, the document has provided clear indications and contraindications for performing AF ablation procedures. This has been very useful in discussing the complexities of the procedure with patients. Second, the consensus document has clarified that electrical isolation of the pulmonary veins is the primary objective of an AF ablation procedure, particularly when performed for patients with paroxysmal atrial fibrillation.
       Third, the document has provided fairly specific advice concerning anti-coagulation strategies prior to, during, and following AF ablation procedures. And finally, the consensus document has clarified the length of the blanking period following AF ablation, which helps determine when repeat ablation procedures should be considered.
       An additional component of the statement, which has been well received by the EP community, is the detailed description of the potential complications associated with AF ablation. This has been particularly useful to clinicians who are faced with deciding when some of the most serious complications, such as an atrial - esophageal fistula, should be screened for.
       The Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation has also had a positive impact on the community of academic electrophysiologists who are involved in reporting the outcomes of clinical trials of AF ablation.
       Soon after the consensus document was published, reviewers for many of the major medical journals have insisted that the consensus statement’s recommendations for reporting outcomes be adhered to.
       This includes using a standardized definition of success: "Freedom from symptomatic or asymptomatic atrial fibrillation/flutter/ tachycardia or more than 10 minutes duration off antiarrhythmic drug therapy"; as well as insisting that clinical trials report single procedure outcomes.
       Another important recommendation of the consensus document was that compliance with monitoring protocols for asymptomatic atrial fibrillation be provided and the results of this monitoring reported. It is reassuring to see that reviewers of articles for medical journals are voluntarily acting as "policemen" to raise the standards for reporting the outcomes of clinical trials of AF ablation to those recommended by the Consensus Document.
       It is clear that this consensus statement has had a significant impact in the EP medical commuity. Patient care is improving and the quality of clinical research in this field is also witnessing improvement in its standards and guidelines.

Summary of Expert Panel Discussion: Adopting and Implementing the AF Ablation Consensus Statement
       Doug L. Packer, MD, co-chair of the AFib Summit, convened members of the expert panel discussion, stating to the audience that panelists would provide their opinion on the document: where it fits in the treatment of AF and guidelines in general, where it fits overall in the management of AF, and what impact it may have on the practice of medicine.
       Peter R. Kowey, MD, session chair, argued that the consensus statement should not be used as a guideline, as it merely summarizes opinions and does not include solid data to support any of the approaches. Albert L. Waldo, MD, echoed that sentiment, insisting the document is state-of-the-art and should not be considered a guideline; despite the opinion of these two experts, the statement does outline the need for more clinical trials in order to obtain data that is lacking.
       Josep Brugada, MD, PhD, elaborated that the growing technique for AF ablation has been expanding so fast there has been no time to provide highly accurate data. Still, he believes a consensus agreement based on the input of experienced physicians is important, as it shows the status of what physicians performing AF ablation know and summarizes the latest expert opinions with regard to this technique.
       Kenneth Ellenbogen, MD, explained that the clinical trials section of the document is important, as it has established a framework to guide investigators so trials will be reported in a uniform way. In addition, he said the statement is valuable to physicians because it outlines what information to tell patients. For example, the vocabulary section provides definitions on the various types of AF, complications, appropriate follow-up, and success and failure. David J. Callans, MD, stated that the document provides a framework on the minimal standards for how efficacy and safety results should be reported. He urged EPs to maintain these minimal standards so credibility is not lost.
       Paul A. Friedman, MD, said the document highlights the importance of educating both patients and referring physicians, and believes the consensus will have a true impact on patient outcomes. The document will set expectations, for instance, by letting patients know potential complications and how they are presented. “The document’s strength is providing a dialog for future research and a state-of-the art summary that will hopefully improve patient care,” stated Dr. Friedman.