Highlights of the Updated Atrial Fibrillation Ablation Consensus Statement

The 2007 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation (AF) was recently updated. This document is a useful reference for those involved in interventional procedures for AF. Important changes from the prior statement include a summary of the indications for ablation and surgery for AF using the standard ACC/AHA guideline format, a discussion of peri-procedural anticoagulation management, a list of standardized definitions, and a framework for future clinic trials. The document is an important step forward for a procedure that continues to evolve.

Based on the availability of additional evidence demonstrating that catheter ablation is safe and effective, including data from landmark clinical trials such as the STOP-AF trial, the Consensus Statement has elevated catheter ablation for symptomatic paroxysmal AF, that is refractory or intolerant to at least one Class 1 or 3 antiarrhythmic medication, to a Class I recommendation with level of evidence A. All other indications for catheter ablation were determined to be Class IIa or IIb. There were no Class I indications for stand-alone surgical ablation, and stand-alone surgery was determined to be contraindicated in patients with symptomatic AF prior to a trial of antiarrhythmic drug therapy.

Definitions of terms used to categorize types of AF and to define successful ablation were also included in the updated document.

• An episode of AF was defined as AF that is documented by ECG monitoring and has a duration of ≥30 seconds, or if less than 30 seconds, is present continuously throughout the ECG monitoring tracing.
• The use of the term ‘permanent AF’ was discouraged and determined not to be appropriate in the context of patients undergoing catheter or surgical ablation of AF. A better term to describe AF that has been continuous for a very long period of time is ‘longstanding persistent AF,’ which was defined as continuous for >12 months.
• Paroxysmal AF was defined as AF that terminates spontaneously within 7 days, or is cardioverted within ≤48 hours.

Areas of consensus included:

• Low molecular weight heparin or intravenous heparin should be used as a bridge to resumption of systemic anticoagulation following AF ablation.
• Oral anticoagulation is recommended for all patients for at least two months following an AF ablation procedure.
• Decisions regarding the use of oral anticoagulation for more than two months following ablation should be based on the patient’s risk factors for stroke and not on the presence or type of AF.
• The primary endpoint of AF ablation is freedom from AF/flutter/tachycardia off antiarrhythmic therapy.
• 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.
• An episode of AF/flutter/tachycardia detected by monitoring should be considered a recurrence if it has a duration of 30 seconds or more.

Interesting statistics on the proportion of writers who follow certain protocols during AF ablation procedures were described, and included:

• 50% perform AF ablation on therapeutic anticoagulation.
• 90% use a three-dimensional mapping system.
• 50% use intracardiac echo to guide transseptal catheterization.
• 50% perform pulmonary venography during the procedure.
• 66% use an esophageal temperature probe and 75% decrease the radiofrequency power when ablating posteriorly in the left atrium.
• 66% routinely use proton pump inhibitors or histamine blockers post procedurally.

The updated AF Ablation Consensus Statement does a good job of acknowledging that there is more than one way to safely and effectively perform AF ablation, summarizing important areas of consensus, and reporting the frequency with which various techniques and strategies are being used by experienced centers in areas where there is no consensus. It emphasizes that despite significant progress in interventional AF therapy, many questions remain unanswered.

Reference

1. Calkins H, Kuck KH, Cappato R, et al. 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. Heart Rhythm 2012 March 1. [Epub ahead of print]