Indications for Atrial Fibrillation Ablation and Consensus Recommendations



Indications for Atrial Fibrillation Ablation and Consensus Recommendations


Hugh Calkins



The HRS/EHRA/ECAS Expert Consensus Document on Catheter and Surgical Ablation of Atrial Fibrillation was published in June 2007 (1). The purpose of the Consensus Statement is to provide a state-of-the-art review of the field of catheter and surgical ablation of atrial fibrillation (AF), and to report the findings of a task force charged with defining the indications, techniques, and outcomes of these procedures. It was the hope of those involved in writing this document that this Consensus Statement would improve patient care by providing a foundation of knowledge for those involved with catheter ablation of AF and would also help standardize the reporting of clinical trials of catheter ablation of AF. The task force writing committee was composed of members representing the American College of Cardiology, the American Heart Association, the European Cardiac Arrhythmia Society, the European Heart Rhythm Association, the Society of Thoracic Surgeons, and the Heart Rhythm Society.

This document summarizes the opinion of the task force members based on their experience and a review of the literature. In addition, a draft of the document was reviewed by other experts representing the participating organizations. In writing a “consensus” document, it was recognized that consensus does not mean that there was complete agreement among all task force members. The writing group attempted to identify those aspects of the field of catheter ablation of AF for which a true consensus could be identified. Anonymous surveys of the entire task force were used to identify these areas of consensus, which are stated in Tables 1.1 and 1.2 of this chapter.

The purpose of this chapter is to review and highlight those aspects of the Consensus Statement that are likely to have the largest impact on the management of patients undergoing or being considered for catheter ablation of AF. Also reviewed
are several aspects of the Consensus Document that impact the reporting of outcomes as part of clinical trials on catheter ablation of AF.








TABLE 1.1 Areas of Consensus: Definitions, Indications, Technique, and Laboratory Management























AF Definition




  • Paroxysmal AF is defined as recurrent AF (≥2 episodes) that terminates spontaneously within 7 days.



  • Persistent AF is defined as AF sustained beyond 7 days, or lasting less than 7 days but necessitating pharmacologic or electrical cardioversion.



  • Longstanding persistent AF is defined as continuous AF of greater than 1 year duration.



  • The term permanent AF is not appropriate in the context of patients undergoing catheter 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, including catheter or surgical ablation.


Indications for Catheter AF Ablation




  • Symptomatic AF refractory or intolerant to at least one class I or class III antiarrhythmic medication.



  • In rare clinical situations, it may be appropriate to perform AF ablation as 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.


Indications for Surgical AF Ablation




  • Symptomatic AF patients undergoing other cardiac surgery.



  • Selected asymptomatic AF patients undergoing cardiac surgery in whom the ablation can be performed with minimal risk.



  • Stand-alone AF surgery should be considered for symptomatic AF patients who prefer a surgical approach, have failed one or more attempts at catheter ablation, or are not candidates for catheter ablation.


Preprocedure Management




  • Patients with persistent AF who are in AF at the time of ablation should have a TEE performed to screen for thrombus.


Technique and Lab Management




  • Ablation strategies that target the 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.



  • Careful identification of the PV ostia is mandatory to avoid ablation within the PVs.



  • If a focal trigger is identified outside a PV at the time of an AF ablation procedure, it should be targeted if possible.



  • If additional linear lesions are applied, line completeness should be demonstrated by mapping or pacing maneuvers.



  • Ablation of the cavotricuspid isthmus is recommended only in patients with a history of typical atrial flutter or inducible cavotricuspid isthmus-dependent atrial flutter.



  • If patients with longstanding persistent AF are approached, ostial PV isolation alone may not be sufficient.



  • Heparin should be administered during AF ablation procedures to achieve and maintain an ACT of 300 to 400 sec.



Definitions and Indications for Catheter Ablation


Definitions

An initial topic covered in the Consensus Document are the definitions used to classify various types of AF. This is important because in the past a large number of terms were
used to describe types of AF, often with considerable overlap. Also, numerous inconsistencies had arisen between published studies. The Consensus Document proposes that the following definitions of AF types be used in all future studies of AF ablation. Paroxysmal AF is defined as recurrent AF (≥2 episodes) that terminates spontaneously within seven days. Persistent AF is defined as AF that is sustained beyond 7 days, or that lasts
less than 7 days but necessitates pharmacologic or electrical cardioversion. Included within the category of persistent AF is longstanding persistent AF, defined as continuous AF of greater than 1 year duration. The term permanent AF is defined as AF in which cardioversion has either failed or not been attempted. The task force felt that the term permanent AF is not appropriate in the context of patients undergoing catheter and/or surgical 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, including catheter or surgical ablation. The task force also felt that the term chronic AF is vague and also should no longer be used to describe populations of patients undergoing AF ablation.








TABLE 1.2 Areas of Consensus: Postprocedure, Follow-up, and Clinical Trial Considerations







































Postprocedure Management




  • Low molecular weight heparin or intravenous heparin should be used as a bridge to resumption of systemic anticoagulation following AF ablation.



  • Warfarin is recommended for all patients for at least 2 months following an AF ablation procedure.



  • Decisions regarding the use of warfarin more than 2 months following ablation should be based on the patient’s risk factors for stroke and not on the presence or type of AF.



  • Discontinuation of warfarin therapy postablation is generally not recommended in patients who have a CHAD score ≥2.


Follow-up and Clinical Trial Considerations

Blanking period


  • A blanking period of 3 months should be employed after ablation when reporting outcomes.

Definition of success


  • 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.



  • Atrial flutter and other atrial tachyarrhythmias should be considered 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.

Minimal monitoring


  • Patients should be seen in follow-up at a minimum of 3 months following the ablation procedure and then every 6 months for at least 2 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 document by ECG and lasts at least 30 seconds.



  • All patients in a clinical trial should be followed for a minimum of 12 months.



  • Patients being evaluated as part of a clinical trial or in whom warfarin 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 3- to 6-month intervals for 1 to 2 years following ablation.

Repeat procedures


  • Repeat procedures should be delayed for at least 3 months following initial ablation, if the patient’s symptoms can be controlled with medical therapy.

Complication reporting


  • Major complications are defined as those that result in permanent injury or death, require intervention for treatment, or prolong or require hospitalization.

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Aug 18, 2016 | Posted by in CARDIOLOGY | Comments Off on Indications for Atrial Fibrillation Ablation and Consensus Recommendations

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