The recently published “2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation: Recommendations for Patient Selection, Procedural Techniques, Patient Management and Follow-up, Definitions, Endpoints, and Research Trial Design”, written by Calkins H, MD, FACC, FHRS, FAHA, et.al., is as noted on its title page “A report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation. This report was “Developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology (ESC) and the European Cardiac Arrhythmia Society (ECAS); and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS)” and was “Endorsed by the governing bodies of the American College of Cardiology Foundation, the American Heart Association, the European Cardiac Arrhythmia Society, the European Heart Rhythm Association, the Society of Thoracic Surgeons, the Asia Pacific Heart Rhythm Society, and the Heart Rhythm Society.”

The first edition of this consensus statement, published in 2007 in the journal Heart Rhythm, was a very welcome statement from the clinical electrophysiologist’s perspective, in that the report either succeeded or at least attempted to provide a definition of the various types or presentations of atrial fibrillation, a summary of the current understanding of the mechanisms of atrial fibrillation, a consensus on the acceptable approaches to treatment of atrial fibrillation including antiarrhythmic drug therapy and ablation, a consensus on the appropriate minimum follow-up of patients undergoing atrial fibrillation ablation, and guidelines on the design of new studies to assess atrial fibrillation ablation methods and outcomes. In addition, the original consensus statement provided some insight into the role, approach and efficacy of surgical ablation methods for treatment of atrial fibrillation.

There are a few, yet very important differences between these two consensus statements, now some 5 years apart, which will likely have significant impact on clinical electrophysiology practice relative to the management of patients with atrial fibrillation, and particularly with respect to ablation of atrial fibrillation. These differences in consensus statements are based on a large body of literature on ablation of atrial fibrillation that has been published in the intervening 5 years.

A general, major difference in the current consensus statement on AF ablation compared to the first statement in 2007, is the reporting of the percentage of Task Force members who individually or whose centers perform AF ablation procedures and related pre- and post-operative management in a certain manner. It is useful to the reader to have an estimation of the percentage of experts who practice in a certain manner, compared to the “consensus” or majority who practice in a certain manner, which was the format of the first consensus statement that was written on AF ablation in 2007.

Another major difference in the current consensus statement, and one of particular importance, is the definition of atrial fibrillation with respect to its presentation in individual patients. The new consensus statement defines paroxysmal atrial fibrillation as “recurrent AF (≥2 episodes) that terminates spontaneously within 7 days, or episodes of AF of ≤48 hours duration that are terminated with electrical or pharmacologic cardioversion”. Furthermore, it defines persistent atrial fibrillation as “continuous AF that is sustained beyond seven days, or episodes of AF in which a decision is made to electrically or pharmacologically cardiovert the patient after ≥48 hours of AF, but prior to 7 days”. This differs from the prior consensus statement which defined persistent AF as any episode requiring electrical or pharmacological cardioversion. The newer consensus statement is more consistent with the potential mechanisms of atrial fibrillation and the typical approach to ablation of atrial fibrillation. With respect to the definition of long-standing persistent AF and and permanent AF the consensus statements are consistently appropriate.

A new development in the 2012 consensus statement is the classification of indications for AF ablation including class I, IIa, IIb, and III indications, and the inclusion of the level of evidence A-C for such indications. The 2007 consensus statement somewhat altered practice by stating that patients should in most cases receive a trial of antiarrhythmic medication (class Ia or III antiarrhythmic drugs) before attempted ablation. In fact, the 2007 consensus statement suggested that only “In rare clinical situations, it may be appropriate to perform AF ablation as first line therapy”, but the indications were really not spelled out clearly. Thus, in many institutions there was a shift from use of AF ablation as primary therapy, to first a trial of antiarrhythmic therapy before ablation was considered. In contrast, the 2012 consensus statement clearly states that primary AF ablation for paroxysmal atrial fibrillation is a class IIa indication with level of evidence B. This would support the use of AF ablation as first line therapy for selected patients with paroxysmal atrial fibrillation, who prefer to undergo ablation rather than a trial of antiarrhythmic drug therapy. In clinical practice there are a significant percentage of patients who do not want to take antiarrhythmic medications and would prefer a primary ablation approach.

Another significant difference in the consensus statements between 2007 and 2012 which impacts clinical practice is the recommendation for a trans-esophageal echocardiogram. In the 2007 consensus statement it was recommended that all patients in persistent AF undergo TEE prior to ablation, despite the status of their anticoagulation prior to ablation (i.e. INR). The current 2012 consensus statement recommends that in patients with AF persisting <48 hours, that a TEE is not mandatory if their anticoagulation had been sufficient (i.e. INR in the therapeutic range between 2-3) for the three weeks prior to ablation.

The current consensus statement reflects the availability of newer anticoagulation agents (i.e. including the factor Xa and direct thrombin inhibitors), which may now be used instead of warfarin both before and following AF ablation. The consensus statement again recommends that these agents be administered for a minimum of 2 months following ablation, and thereafter decisions regarding anticoagulation therapy depend on the patients CHADS2 or CHA2DS2VASc score, with a score of 2 of greater usually indicating the need for continued anticoagulation with one of the newer oral anticoagulation agents or warfarin. In addition, more detail for use by the operator is provided in this edition of the consensus statement on AF ablation with regards to pre-, intra- and post-procedural anticoagulation with intravenous heparin, low molecular weight heparin, and oral anticoagulants.

The current consensus statement benefits from the additional time that has passed from the original 2007 statement and the additional experience gained in AF ablation. One area where more specific recommendations have arisen as a result of this additional experience is in the recommendations for surgical ablation of AF. In the present statement stand-alone surgical ablation of AF is given a class IIB indication in patients who are refractory to either a class 1 or 3 antiarrhythmic drug and who prefer to have surgery over catheter ablation, but a class III indication for stand-alone surgical AF ablation in patients who have not been tried on an antiarrhythmic drug. In other words, stand-alone surgical ablation of AF is not recommended at a first-line therapy.

The current consensus statement on AF ablation also provides greater detail for the electrophysiologist on the minimum recommended follow-up methodology in patients after AF ablation. The current consensus statement also provides detailed definitions for use when reporting outcomes of clinical trials, greater detail on the design requirements of clinical trials on AF ablation, and a review of ongoing clinical trials on AF ablation (many of which were only in the pilot or planning phase at the time of the 2007 consensus statement of AF ablation).

The prior and current consensus statements on AF ablation ask a number of pertinent questions regarding AF ablation. Many of the questions asked in the first consensus statement on AF ablation in 2007, have now been answered in the current statement. In the current statement, new questions have been asked. Among the twelve questions asked, of particular importance in this reviewers opinion, are the following questions:

1. What is the long-term impact of catheter or surgical AF ablation on stroke risk, the development of heart failure, and major morbidity and mortality?
2. What are the comparative success rates of various ablative techniques in differing patient populations, particularly persistent and longstanding persistent AF?
3. Are there patients in whom oral anticoagulation can be safely discontinued following ablation, and what is the impact of direct thrombin inhibitors and factor Xa inhibitors on anticoagulation strategies prior to, during and following AF ablation?
4. Is there acceptable rationale for ablation applied as first line therapy for AF?
5. What are the very long-term outcomes (˃5 years) of catheter and surgical AF ablation?

Finally, in the current consensus statement there is greater detail and information provided on a variety of issues, including current technologies that may be available to improve AF ablation outcome, more detailed descriptions of endpoints for linear ablation and use of provocative agents (e.g. ATP, adenosine) to elicit dormant PV conduction, newer technologies for ablation of AF such as contact force measuring catheters and irrigated catheters, use of newer energy sources for AF ablation (e.g. cryoablation, laser ablation, etc.), description of potential complications and methods to avoid them, and training requirements, just to mention a few areas of importance.

References

1. Calkins H, et.al. 2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation: Atrial Fibrillation: Definitions, Mechanisms, and Rationale for Ablation. Heart Rhythm 2012; [Epub ahead of print] PubMed.
2. Calkins H, et.al. HRS/EHRA/ECAS expert Consensus Statement on catheter and surgical ablation of atrial fibrillation: recommendations for personnel, policy, procedures and follow-up. A report of the Heart Rhythm Society (HRS) Task Force on catheter and surgical ablation of atrial fibrillation. Heart Rhythm 2007; 4:816-61.
3. Wann LS, et.al. 2011 ACCF/AHA/HRS focused update on the management of patients with atrial fibrillation (Updating the 2006 Guideline): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Heart Rhythm 2011; 8:157-76.

Keywords: Adenosine, American Heart Association, Anticoagulants, Atrial Fibrillation, Catheter Ablation, Catheters, Consensus, Electrophysiology, Heart Failure, Heparin, Low-Molecular-Weight, Stroke, Warfarin

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