BAFS: New AF ablation guidelines to weigh real-life practice considerations
BOSTON--The Heart Rhythm Society, along with other societies, is currently revising the atrial fibrillation (AF) ablation consensus statement, last issued in 2007, paying particular attention to ablation developments, new anticoagulation options and the use of transesophageal echocardiography, according to a presentation Jan. 13 at the Boston AF Symposium (BAFS).

The 2007 Expert Consensus Statement on Catheter and Surgical Ablation of AF, which was jointly developed with European Heart Rhythm Association and European Cardiac Arrhythmia Society, sought to define the indications, techniques and outcomes of AF ablation procedures. The statement was endorsed by the American Heart Association, the American College of Cardiology and the Society of Thoracic Surgeons.

“What needs to be revised, since the 2007 document has been issued?" asked Hugh G. Calkins, MD, director of electrophysiology at Johns Hopkins Medical Institutions in Baltimore, who reviewed the interim consensus process.

Below are a few topics that Calkins et al are re-considering for the new consensus statement—scheduled to be unveiled at the 2012 BAFS.

AF Definitions

In the 2007 guidelines, the three types of AF were defined as such:
  • Paroxysmal AF: Recurrent AF that terminates spontaneously within seven days.
  • Persistent AF: AF that is sustained beyond seven days, or lasting less than seven days but necessitating pharmacologic or electrical conversion.
  • Long-standing Persistent AF (which was a new term with the emergence of the 2007 guidelines): Continuous AF of greater than one-year duration.
  • Permanent AF: The term permanent AF is not appropriate in the context of patients undergoing AF ablation as it refers to a group of patients where a decision has been made not to pursue restoration of sinus rhythm by any means.

Calkins pointed out that a couple of these definitions have resulted in uncertainty, including long-standing persistent AF. “It’s clear that 12 months or longer identifies the group of patients that respond less well to AF ablation, but we have seen that at two or three years is even a lower responding group, so we may need to break this into subsets,” he said.

Also, the authors did not take into consideration failure of cardioversion or cardioversion-resistant patients.

“It’s important to appropriately define the patient population, so we will spend some time in the new guidelines trying to define some of these,” Calkins said.

Indications for Cather Ablation

The 2007 guidelines defined the indications as such:
  • Symptomatic AF refractory or intolerant to at least one Class 1 or Class 3 anti-arrhythmic medication.
  • In rare clinical situations, it may be appropriate to perform AF ablation as a first-line therapy.
  • Selected symptomatic patients with heart failure and/or reduced ejection fraction.
  • The presence of a left atrial thrombus is a contraindication to catheter ablation of AF.

“While there is increasing data suggesting first-line use of AF catheter ablation is reasonable, in most patients, it should remain a second-line therapy because of the risks involved,” Calkins said.

Prior to the procedure, Calkins also pointed out that trasnesophageal echo (TEE) is increasingly being used in patient management. For the new guidelines, “we will really need to consider which patients can skip a TEE,” he said.

Definition of Ablation Success

The authors of the 2007 consensus statement defined success as:
  • A blanking period of three months should be employed after ablation when reporting outcomes.
  • Freedom from AF/flutter/tachycardia and to be off anti-arrhythmic 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 under-represent the 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.
  • Atrial flutter and other atrial tachyarrhythmias should be considered as treatment failures.
  • 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 trials of catheter ablation of AF.

Based on multiple documents published since the 2007 statement, “there seems to be gener
al agreement about the 30-second rule, even though it is a very high bar,” Calkins said. “However, we will look into whether we should have a different definition of success for persistent and long-standing AF.”

Calkins acknowledged that the 2007 document helped “advance research by providing a set of definitions” for practitioners, as “most of the recommendations have been implemented into clinical practice."

In addition to the new anticoagulant options and the preprocedural management with TEE, the new consensus statement also will consider one of the “most important unknown technical issues involving AF ablation,” which is the approach to long-standing persistent AF, said Calkins, who added that cryoballoon ablation also will addressed.