(BQ) Part 1 book Practical approach to catheter ablation of atrial fibrillation presents the following contents: Introduction and historical perspective, ablation program planning, mapping, imaging, and guidance systems.
Trang 3A Practical Approachto Catheter Ablationof Atrial FibrillationEditorsHUGHCALKINS, MDProfessor of Medicine
Johns Hopkins University School of Medicine
Director of the Arrhythmia Service and Clinical Electrophysiology LaboratoryJohns Hopkins Hospital
Baltimore, Maryland
PIERREJẠS, MD
Professor
Department of Cardiology
Université Victor Segalen–Bordeaux 2Hơpital Cardiologique du Haut LévèqueCardiology Department
Bordeaux, France
JONATHANS STEINBERG, MD
Chief, Division of Cardiology
Endowed Director, Al-Sabah Arrhythmia InstituteSt Luke's and Roosevelt Hospitals
New York, New YorkDirector, ElectrophysiologyValley Hospital
Ridgewood, New JerseyProfessor of Medicine
Trang 4Acquisitions Editor: Frances R DeStefanoManaging Editor: Chris Potash
Marketing Manager: Kimberly SchonbergerProject Manager: Bridgett Dougherty
Senior Manufacturing Manager: Benjamin RiveraCreative Director: Doug Smock
Compositor: Aptara Inc.
© 2008 by LIPPINCOTT WILLIAMS & WILKINS
All rights reserved This book is protected by copyright No part of this book may be reproduced in anyform or by any means, including photocopying, or utilized by any information storage and retrieval systemwithout written permission from the copyright owner, except for brief quotations embodied in critical arti-cles and reviews Materials appearing in this book prepared by individuals as part of their official duties asU.S government employees are not covered by the abovementioned copyright
Printed in the USA
Library of Congress Cataloging-in-Publication Data
A practical approach to catheter ablation of atrial fibrillation / editors, Hugh Calkins, Pierre Jạs, Jonathan S Steinberg.
p ; cm.
ISBN-13: 978-0-7817-7559-5 (alk paper)ISBN-10: 0-7817-7559-0 (alk paper)
1 Catheter ablation 2 Atrial fibrillation—Surgery I Calkins, Hugh, 1956– II Jạs, Pierre, 1964– III.Steinberg, Jonathan S.[DNLM: 1 Atrial Fibrillation—surgery 2 Catheter Ablation—methods WG 330 P8948 2008]RD598.35.C39P73 2008 617.4'120592—dc222008006111Care has been taken to confirm the accuracy of the information presented and to describe generally acceptedpractices However, the authors, editors, and publisher are not responsible for errors or omissions or for anyconsequences from application of the information in this book and make no warranty, expressed or implied,with respect to the currency, completeness, or accuracy of the contents of the publication Application ofthis information in a particular situation remains the professional responsibility of the practitioner
The authors, editors, and publisher have exerted every effort to ensure that drug selection and dosageset forth in this text are in accordance with current recommendations and practice at the time of publica-tion However, in view of ongoing research, changes in government regulations, and the constant flow ofinformation relating to drug therapy and drug reactions, the reader is urged to check the package insert foreach drug for any change in indications and dosage and for added warnings and precautions This is particu-larly important when the recommended agent is a new or infrequently employed drug
Some drugs and medical devices presented in this publication have Food and Drug Administration(FDA) clearance for limited use in restricted research settings It is the responsibility of the health careprovider to ascertain the FDA status of each drug or device planned for use in their clinical practice.
Trang 5To Alice, Rachel, and Josh, whose encouragement and support made all this effort possible
—JS
To Beth, Emily, Eliza, and Daniel
Trang 7CO N T E N T S
Contributing Authors xiPreface xxiii
I Introduction and Historical Perspective 11 Indications for Atrial Fibrillation Ablation
and Consensus Recommendations 3
Hugh Calkins
2 Nonpharmacological Therapy for Atrial Fibrillation:
An Historical Overview 11
David A Spragg, Hugh Calkins
II Ablation Program Planning 253 Equipment and Staffing 27
David Haines
4 Preprocedure Preparation 37
Jose F Huizar, Karoly Kaszala,
Mark A Wood, Kenneth A Ellenbogen
III Mapping, Imaging, and Guidance Systems 555 Intracardiac Ultrasound 57
Jonathan S Steinberg, Jayanthi Koneru,Kataneh Maleki, Farooq Chaudhry
6 Electroanatomic Mapping Systems 83
Anshul M Patel, Vivek Y Reddy
7 Magnetic and Robotic Navigation 100
Bruce D Lindsay, Mitchell Faddis
8 Noncontact Mapping 118
Satoshi Higa, Yenn-Jiang Lin,Ching-Tai Tai, Shih-Ann Chen
Trang 8IV Ablation Procedures 1359 Circumferential Ablation with PV Isolation Guided
by Lasso Catheter 137
Feifan Ouyang, Kazuhiro Satomi, Karl-Heinz Kuck
10 Circumferential Atrial Ablation 167
Carlo Pappone, Vincenzo Santinelli
11 Electrogram-Guided Ablation 184
Evan Lockwood, Koonlawee Nademanee
12 Linear Left Atrial Ablation 198
Mélèze Hocini, Kang-Teng Lim, Prashanthan Sanders, Pierre Jạs, Seiichiro Matsuo, Sébastien Knecht, Leonardo Arantès, Mark O’Neill, Yoshihide Takahashi,Jacques Clémenty, Michel Hạssaguerre
13 Tailored Approach to Ablation 210
Hakan Oral, Fred Morady
14 Ablation of Autonomic Ganglia 218
Hiroshi Nakagawa, Katsuaki Yokoyama, Benjamin Scherlag, Vikram Katari,
Hiroshi Aoyama, Sara Foresti, Warren Jackman
15 Atrial Fibrillation Trigger Mapping 231
Francis Marchlinski, Fermin Garcia
V Ablation Strategies 24916 A Comprehensive Overview of Ablation of
Paroxysmal, Persistent, and Permanent Atrial
Fibrillation: A Stepwise Approach 251
Pierre Jạs, Seiichiro Matsuo, Kang-Teng Lim,
Mélèze Hocini, Sébastien Knecht, Leonardo Arantès, Pierre Bordachar, Jacques Clémenty, Michel Hạssaguerre
17 Emerging Technologies 260
Trang 918 Identification and Elimination of Ancillary Arrhythmias 273
Paolo Ferrero, Pietro Francia, Riccardo Cappato
19 Ablation Procedure Follow-up and Definitions
of Success 281
Christopher Piorkowski, Gerd Hindricks, Hans Kottkamp
20 When and How to Re-Ablate 292
Michael Riley, David Callans
21 Postprocedural Care after Radiofrequency
Catheter Ablation for Atrial Fibrillation 310
Alan Wimmer, Hakan Oral
22 Complications 320
Conor Barrett, Robert Schweikert,Walid Saliba, Jennifer Cummings,J David Burkhardt, Oussama Wazni, Andrea Natale
23 The Challenges of Monitoring Outcomes 346
Isabel Deisenhofer
Trang 11CO N T R I B U T I N GAU T H O R S
Hiroshi Aoyama, MD, PhD
Research fellow
Department of Medicine
University of Oklahoma Health Sciences CenterOklahoma City, Oklahoma
Aysha Arshad, MD
Assistant ProfessorDepartment of Cardiology
St Luke’s and Roosevelt HospitalsNew York, New YorkLeonardo Arantès, MDAssistant ProfessorDepartment of CardiologyGama Filho UniversityElectrophysiology AdvisorDepartment of CardiologyHơpital São José
Rio de Janeiro, Brazil
Conor D Barrett, MB, Bch, MRCPI
Clinical Fellow, Section of ElectrophysiologyDepartment of Cardiovascular MedicineCleveland ClinicCleveland OhioPierre Bordachar, MDUniversité Victor Segalen and Hơpital Cardiologique du Haut-Lévêque Bordeaux, FranceJ David Burkhardt, MD
Associate Fellowship Director
Department of Cardiovascular MedicineCleveland Clinic
Cleveland Ohio
Trang 12Hugh Calkins, MD
Professor, of MedicineDepartment of Medicine
Johns Hopkins University School of Medicine
Director of the Arrhythmia Service and Clinical EP LaboratoryJohns Hopkins HospitalBaltimore, Maryland David J Callans, MDProfessor Department of MedicineUniversity of Pennsylvania
Associate Director, ElectrophysiologyHospital of the University of Pennsylvania Philadelphia, Pennsylvania
Riccardo Cappato, MD
Director
Center of Clinical Arrhythmia and ElectrophysiologyIRCCS Policlinico San Donato
Milan, Italy
Farooq A Chaudhry, MD, FACC, FASE
Associate Professor of MedicineDepartment of Medicine
Columbia University College of Physicians and Surgeons Director of Echocardiography; Associate Chief of CardiologyDepartment of Medicine
St Luke’s and Roosevelt HospitalsNew York, New York
Shih-Ann Chen, MD
Professor of MedicineDepartment of MedicineNational Yang-Ming University
Director of Cardiac Electrophysiology LaboratoryDivision of CardiologyTaipei Veterans General HospitalTaipei, TaiwanAndrew Choi, BAResearch FellowDivision of Cardiology
Trang 13Jacques Clémenty, MD ProfessorCardiology DepartmentUniversité Victor Segalen and Hơpital Cardiologique du Haut-Lévêque Bordeaux, FranceJennifer E Cummings, MDDirector of EP ResearchDepartment of Cardiovascular MedicineCleveland ClinicCleveland, OhioIsabel Deisenhofer, MDJunior ProfessorDepartment of CardiologyTechnische University MünchenFellow Department of CardiologyGerman Heart CenterMunich, GermanyKenneth A Ellenbogen, MDKontos Professor of CardiologyDepartment of Medicine
Virginia Commonwealth University/Medical College of VirginiaDirector, EP & Pacing Laboratory Medical College of VirginiaRichmond, Virginia
Mitchell N Faddis, MD, PhD
Associate Professor of Medicine
Internal Medicine/Cardiovascular DiseasesWashington University School of MedicineCardiac ElectrophysiologistInternal Medicine/CardiologyBarnes HospitalSt Louis, MissouriPaolo Ferrero, MD
Research and Clinical Fellow
Center of Clinical Arrhythmia and ElectrophysiologyIRCCS Policlinico San Donato
Trang 14Sara Foresti, MD
Research Fellow Department of Medicine
University of Oklahoma Health Sciences CenterOklahoma City, Oklahoma
Pietro Francia, MD
Research and Clinical Fellow
Center of Clinical Arrhythmia and ElectrophysiologyIRCCS Policlinico San Donato Milan, Italy Fermin C Garcia, MDAssistant Professor of Medicine Department of Medicine University of Pennsylvania Cardiac Electrophysiologist Department of MedicineHospital of the University of Pennsylvania Philadelphia, PADavid E Haines, MD
Corporate Chief of Cardiovascular Medicine and Medical Directorof the Heart Rhythm Center
Department of Internal MedicineWilliam Beaumont HospitalRoyal Oak, MichiganMichel Hạssaguerre, MDProfessorDepartment of CardiologyUniversité Victor Segalen and Hơpital Cardiologique du Haut-LévêqueBordeaux, FranceSatoshi Higa, MD, PhD
Assistant Professor of Medicine
Second Department of Internal MedicineUniversity of the Ryukyus School of MedicineDirector of Clinical Electrophysiology LaboratoryChief of Cardiology Division
Trang 15Gerd Hindricks, MD, PhDProfessorHead of DepartmentDepartment of ElectrophysiologyHeart CenterUniversity of LeipzigLeipzig, GermanyMélèze Hocini, MDAssociate Professor
Cardiac Arrhythmias DepartmentUniversité Victor Segalen—Bordeaux 2Praticien Hospitalier
Cardiac Arrhythmias Department
Hơspital Cardiologique du Haut LévèqueBordeaux, France
Jose F Huizar, MD
Assistant ProfessorDepartment of Medicine
Virginia Commonwealth University/ Medical College of VirginiaDirector, Arrhythmic and Device ClinicDepartment of MedicineHunter Holmes McGuire Virginia Medical CenterRichmond, Virginia Warren M Jackman, MDProfessor of MedicineDepartment of Medicine
Trang 16Karoly Kaszala, MD, PhD
Assistant ProfessorDepartment of Medicine
Trang 17Yenn-Jiang Lin, MDVisiting StaffDivision of CardiologyTaipei Veterans General HospitalTaipei, Taiwan Bruce D Lindsay, MDProfessor of Medicine
Director of Cardiac Electrophysiology Washington University School of MedicineSt Louis, MissouriEvan E Lockwood, MD Assistant ProfessorDepartment of MedicineUniversity of AlbertaCardiac ElectrophysiologistDivision of Cardiology
Mazankowski Alberta Heart InstituteEdmonton, Alberta, Canada
Kataneh Maleki, MD
Assistant ProfessorDivision of Cardiology
St Luke’s and Roosevelt HospitalsNew York, New YorkFrancis E Marchlinski, MDProfessor of MedicineDepartment of MedicineUniversity of PennsylvaniaDirector, Cardiac ElectrophysiologyDepartment of MedicineHospital of the University of PennsylvaniaPhiladelphia, PennsylvaniaSeiichiro Matsuo, MDCardiology DepartmentUniversité Victor Segalen and Hơpital Cardiologique du Haut-LévêqueBordeaux, FranceSuneet Mittal, MD
Trang 18Fred Morady, MD
McKay Professor of Cardiovascular DiseaseCardiovascular Medicine
University of Michigan Health SystemAnn Arbor, MichiganKoonlawee Nademanee, MDDirectorPacific Rim Electrophysiology Research InstituteInglewood, CaliforniaHiroshi Nakagawa, MD, PhDProfessor of MedicineDepartment of Medicine
University of Oklahoma Health Sciences CenterOklahoma City, Oklahoma
Andrea Natale, MD
Trang 19Carlo Pappone, MD, PhDDirector of ArrhythmologyArrhythmology DepartmentOspedale San Raffaele Milano, ItalyAnshul M Patel, MDClinical & Research FellowDepartment of MedicineHarvard Medical School
Fellow in Cardiac ElectrophysiologyCardiac Arrhythmia Service
Massachusetts General HospitalBoston, MassachusettsChristopher Piorkowski, MDDoctor/ConsultantDepartment of ElectrophysiologyUniversity of Leipzig Heart CenterLeipzig, GermanyVivek Y Reddy, MD
Director, Experimental EP LaboratoryCardiac Arrhythmia Service
Trang 20Vincenzo Santinelli, MDProfessor of CardiologyOspedale San RaffaeleScientific DirectorArrhythmologyOsepedale San RaffaeleMilan, ItalyKazuhiro Satomi, MD, PhDCo-Director, EP LaboratoryDepartment of CardiologyNational Cardiovascular CenterSuita, JapanBenjamin J Scherlag, PhDProfessor of MedicineDepartment of Medicine
University of Oklahoma Health Sciences CenterOklahoma City, OklahomaRobert A Schweikert, MDDirector of OperationsDepartment of Cardiovascular MedicineCleveland ClinicCleveland, OhioDavid A Spragg, MDAssistant ProfessorDepartment of MedicineJohns Hopkins University School of MedicineAssistant ProfessorDivision of CardiologyJohns Hopkins HospitalBaltimore, MarylandJonathan S Steinberg, MDProfessor of Medicine
Columbia University College of Physicians & SurgeonsChief, Division of Cardiology
Endowed Director, Al-Sabah Arrhythmia InstituteSt Luke’s and Roosevelt Hospitals
New York, New YorkDirector, ElectrophysiologyValley Hospital
Trang 21Ching-Tai Tai, MD Professor of MedicineDepartment of MedicineNational Yang-Ming University School of MedicineVisiting DoctorDivision of CardiologyTaipei Veterans General HospitalTaipei, Taiwan Yoshihide Takahashi, MDDepartment of CardiologyAnjindaiKanagawa, JapanOussama M Wazni, MDDirector of AF ResearchDepartment of Cardiovascular MedicineCleveland Clinic Cleveland, OhioAlan Wimmer, MDCardiologistElectrophysiology
Department of St, Luke’s HospitalMid America Heart InstituteKansas City, Missouri
Mark A Wood, MD
Professor of Medicine
Department of Internal Medicine/CardiologyVirginia Commonwealth University Medical Center Richmond, Virginia
Katsuaki Yokoyama, MD, PhD
Research AssociateDepartment of Medicine
Trang 23xxiii
PR E F A C E
Interventional electrophysiology has enjoyed a remarkable period of innovation andtechnical advancement, fueled in part by progress in the fundamental understandingof arrhythmia mechanism Perhaps the last great frontier was catheter-based definitivetherapy for atrial fibrillation, the most common sustained cardiac arrhythmia
Atrial fibrillation is a complex arrhythmia involving diverse mechanisms and acomplex interplay of trigger and substrate, and has well-described clinical and func-tional consequences A multidisciplinary and concerted effort to treat atrial fibrilla-tion has ultimately produced a great variety of successful catheter-based techniques.These procedures are more challenging and labor intensive than are most othercatheter ablative interventions and are evolving at a rapid pace, as are support andancillary procedures
This book is designed to provide a comprehensive and practical compendium onhow to establish programs and laboratories to treat atrial fibrillation; how to use com-plex imaging modalities and guidance systems; how to implement a variety ofcatheter-based ablation strategies, either isolated or in tandem; and how to monitorthe ablated patient’s course for complications and arrhythmia recurrence and managethese problems should they arise In short, we have attempted to deliver a practicalguide to all medical professionals who have an interest in catheter ablation of atrialfibrillation.
Trang 25IPART
Trang 271
Hugh Calkins
3
The HRS/EHRA/ECAS Expert Consensus Document on Catheter and SurgicalAblation of Atrial Fibrillation was published in June 2007 (1) The purpose of theConsensus Statement is to provide a state-of-the-art review of the field of catheterand surgical ablation of atrial fibrillation (AF), and to report the findings of a taskforce charged with defining the indications, techniques, and outcomes of these pro-cedures It was the hope of those involved in writing this document that this Con-sensus Statement would improve patient care by providing a foundation of knowl-edge for those involved with catheter ablation of AF and would also help standardizethe reporting of clinical trials of catheter ablation of AF The task force writing com-mittee was composed of members representing the American College of Cardiology,the American Heart Association, the European Cardiac Arrhythmia Society, theEuropean Heart Rhythm Association, the Society of Thoracic Surgeons, and theHeart Rhythm Society.
This document summarizes the opinion of the task force members based on theirexperience and a review of the literature In addition, a draft of the document wasreviewed by other experts representing the participating organizations In writing a“consensus” document, it was recognized that consensus does not mean that there wascomplete agreement among all task force members The writing group attempted toidentify those aspects of the field of catheter ablation of AF for which a true consensuscould be identified Anonymous surveys of the entire task force were used to identifythese 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 Con-sensus Statement that are likely to have the largest impact on the management ofpatients undergoing or being considered for catheter ablation of AF Also reviewed
Indications for AtrialFibrillation Ablation and Consensus
Trang 28are several aspects of the Consensus Document that impact the reporting of out-comes as part of clinical trials on catheter ablation of AF.
Definitions and Indications for Catheter Ablation
Definitions
An initial topic covered in the Consensus Document are the definitions used to classifyvarious types of AF This is important because in the past a large number of terms were
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 sinusrhythm 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 performedwith 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 toscreen 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 targetedif possible.
• If additional linear lesions are applied, line completeness should be demonstrated by mapping or pac-ing maneuvers.
• Ablation of the cavotricuspid isthmus is recommended only in patients with a history of typical atrialflutter 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
TABLE 1.1 Areas of Consensus: Definitions, Indications, Technique, and
Trang 29used to describe types of AF, often with considerable overlap Also, numerous inconsis-tencies 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
Parox-ysmal 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
Postprocedure Management
• Low molecular weight heparin or intravenous heparin should be used as a bridge to resumption ofsystemic 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 aCHAD score 2 Follow-up and Clinical Trial ConsiderationsBlanking 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 afterAF ablation, but may underrepresent true benefit.
• Freedom from AF at various points following ablation may be a better marker of true benefit andshould 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 ithas 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 andthen every 6 months for at least 2 years.
• An event monitor should be obtained to screen for recurrent AF/flutter/tachycardia in patients whocomplain 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 shouldhave 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 aclinical 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’ssymptoms can be controlled with medical therapy
Complication reporting
• Major complications are defined as those that result in permanent injury or death, require interven-tion for treatment, or prolong or require hospitalizainterven-tion.
TABLE 1.2 Areas of Consensus: Postprocedure, Follow-up, and Clinical Trial
Trang 30less than 7 days but necessitates pharmacologic or electrical cardioversion Included
within the category of persistent AF is longstanding persistent AF, defined as continuousAF 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 madenot 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.
Indications for Catheter Ablation
The task force agreed that catheter ablation of AF in general should not be consideredas first line therapy The consensus among the task force was that the primary indicationfor catheter AF ablation is the presence of symptomatic AF refractory or intolerant to atleast one class I or class III antiarrhythmic medication The task force did recognize thatin rare clinical situations, it may be appropriate to perform catheter ablation of AF as firstline therapy Catheter ablation of AF was also considered appropriate in selected symp-tomatic patients with heart failure and/or reduced ejection fraction While some patientswith asymptomatic AF seek catheter ablation as an alternative to long-term anticoagula-tion, this desire by itself should not be considered an appropriate selection criterion.
The presence of a left atrial thrombus was identified as a contraindication tocatheter ablation of AF Another contraindication to catheter ablation of AF is theinability to systemically anticoagulate a patient for at least the first 2 months follow-ing an ablation procedure.
Techniques and Endpoints for Atrial Fibrillation Ablation
A variety of techniques have been developed for catheter ablation of AF These arereviewed in the Consensus Document The task force reached consensus on the fol-lowing recommendations concerning the techniques and endpoints of AF ablation:1 Ablation strategies that target the pulmonary veins (PVs) and/or PV antrum are
the cornerstone for most AF ablation procedures.
2 If the PVs are targeted, complete electrical isolation should be the goal.3 For surgical PV isolation, entrance and/or exit block should be demonstrated.4 Careful identification of the PV ostia is mandatory to avoid ablation within the PVs.5 If a focal trigger is identified outside a PV at the time of an AF ablation
proce-dure, it should be targeted if possible.
6 If additional linear lesions are applied, line completeness should be demonstratedby mapping or pacing maneuvers.
7 Ablation of the cavotricuspid isthmus is recommended only in patients with a his-tory of typical atrial flutter or inducible cavotricuspid isthmus–dependent atrialflutter.
8 If patients with longstanding persistent AF are approached, ostial PV isolationalone may not be sufficient.
Anticoagulation and Strategies to Prevent Thromboembolism
Trang 31as one of the most serious complications of AF and also of AF ablation procedures.For this reason, the task force recommends that the anticoagulation guidelines pub-lished as part of the ACC/AHA/ESC 2006 Guidelines for the Management ofPatients with AF be adhered to (2) In particular, the guidelines for anticoagulation,both for long-term management and also those that apply to cardioversion proce-dures, should be followed In addition to following these anticoagulation guidelines,there was a consensus among the task force members that patients with persistent AFwho are in AF at the time of ablation should have a TEE performed to screen for athrombus The lower level of anticoagulation during an ablation procedure should bemaintained at an ACT of at least 300 to 350 seconds throughout the procedure.After catheter ablation and sheath removal, anticoagulation should be reinitiatedpromptly There was a consensus among the task force members that:
1 Warfarin is recommended for all patients for at least 2 months following an AFablation procedure.
2 Decisions regarding the use of warfarin more than 2 months following ablationshould be based on the patient’s risk factors for stroke and not on the presence ortype of AF.
3 Discontinuation of warfarin therapy postablation is generally not recommended in
patients who have a CHADS score 2.
Despite these rather stringent recommendations, it is recognized that many patientsare highly motivated to discontinue warfarin As with all decisions concerning apatient’s care, the cardiologist and patient need to discuss in detail the risks and ben-efits of discontinuing warfarin Patients with two or more CHADS risk factors needto be informed that if they elect to discontinue warfarin they are accepting a risk ofstroke Furthermore, they need to be informed that no studies to date have shownthat elimination of AF with catheter ablation of AF reduces a patient’s short- or long-term risk of stroke.
Training Requirements and Competencies
The training and competencies required for training in AF ablation differ from otherablation procedures because, in comparison, ablation of AF is more difficult, is asso-ciated with greater risks, and requires more careful follow-up The American Collegeof Cardiology/American Heart Association 2006 update of the clinical competencestatement on invasive electrophysiology studies, catheter ablation, and cardioversionproposes a minimum of 30 to 50 AF ablation procedures for those who undergo fel-lowships in clinical cardiac electrophysiology (3) The task force felt that this numberunderestimates the experience required for a high degree of proficiency Trainees whointend to perform ablation of AF independently should consider additional trainingafter the standard fellowship is completed.
Trang 32Follow-up and Monitoring Guidelines
Arrhythmia monitoring is an important component of the initial evaluation ofpatients who are to undergo catheter ablation procedures for AF ECG monitoringalso plays an important role in the follow-up after an ablation procedure Early recur-rences of AF are common during the first 1 to 3 months following a catheter abla-tion procedure For this reason, arrhythmia monitoring to assess the efficacy ofcatheter ablation is typically delayed for at least 3 months following catheter ablation.Arrhythmia monitoring may be in the form of intermittent sampling using a standardECG or a patient activated event monitor with or without a memory loop Varioustypes of continuous monitoring systems are also available.
There was general agreement among the task force members that all patients whoundergo catheter ablation of AF should be seen in follow-up at a minimum of 3months following the ablation procedure and then every 6 months for at least 2 years.ECGs should be obtained at all follow-up visits and patients who complain of palpi-tations should be evaluated with an event monitor Prior to hospital discharge, it isrecommended that patients receive detailed follow-up instructions and be providedwith contact information that will facilitate prompt evaluation of symptoms consis-tent with a late complication of the ablation procedure Although there was no con-sensus among the task force members on the role of routine imaging studies to screenfor pulmonary vein stenosis, there was general agreement that the threshold for usingimaging tools for symptom evaluation should be low.
Although early recurrence of AF carries an independent risk of treatment failure,its occurrence should not prompt immediate re-ablation attempts, as 20% to 57% ofpatients experiencing this event within the first months postablation will not have anyfurther arrhythmias during long-term follow-up Since the mechanism of AF postab-lation may be different from that of the patient’s clinical arrhythmia and may resolvecompletely upon resolution of the inflammatory process, the Consensus Documentnotes that some operators choose to treat all patients with suppressive antiarrhythmicagents for the first 1 to 3 months following ablation Repeat ablation proceduresshould be delayed for at least 3 months following the initial procedure if the patient’ssymptoms can be controlled with medical therapy.
Outcomes and Efficacy of Catheter Ablation
Until the publication of the Consensus Document, there had been no standardiza-tion in the design of clinical trials of AF ablastandardiza-tion It is now well recognized that theoutcomes of AF ablation differ considerably depending on whether patients haveparoxysmal, persistent, or longstanding persistent AF Similarly, variables such as age,concomitant cardiac disease, and left atrial size are important determinants of out-come Other important considerations are the duration of the blanking period, thefrequency and intensity of arrhythmia monitoring, whether patients with atrial flutterduring follow-up are classified as successes or failures, the use of AADs, and the fre-quency and timing of performance of repeat ablation procedures Each of these fac-tors plays a role in how a particular study defines “success.”
Trang 33trials varied widely Although the single procedure success of catheter ablation ofpatients with paroxysmal AF ranged from 38% to 78%, most series reported a singleprocedure efficacy of 60% or greater In contrast, the single procedure success ofcatheter ablation of patients with persistent AF ranged from 22% to 45%, with mostcenters reporting an efficacy of 30% or less The single procedure success of catheterablation of patients with mixed types of AF ranged from 16% to 84% The reportedmultiple procedure success of catheter ablation of patients with paroxysmal AFranged from 54% to 80%, with most series reporting a multiple procedure efficacy of70% or greater The multiple procedure success of catheter ablation of patients withpersistent AF ranged from 37% to 88%, with most centers reporting a multiple pro-cedure efficacy of 50% or greater The multiple propro-cedure success of catheter ablationof patients with mixed types of AF ranged from 30% to 81%
The Consensus Document also reviews the findings of five randomized studies of AFablation, as well as the findings of a large international survey of catheter ablation of AF(4).The results of the reviewed studies and survey provide substantial evidence of the effi-cacy of catheter ablation for treatment of patients with AF However, it was also clear tothe writing group that outcomes vary considerably Potential factors identified by thewriting group that may impact outcome include: (a) differences in technique, (b) differ-ences in follow-up and definitions of success, (c) differdiffer-ences in the use of antiarrhythmictherapy, and (d) differences in experience and technical proficiency, and so forth.
Surgical Ablation of Atrial Fibrillation
The task force reached the following areas of consensus concerning the indicationsfor surgical AF ablation: (a) symptomatic AF patients undergoing other cardiac sur-gery, and (b) selected asymptomatic AF patients undergoing cardiac surgery in whichthe ablation can be performed with minimal risk Stand-alone AF surgery should beconsidered for symptomatic AF patients who prefer a surgical approach, have failedone or more attempts at catheter ablation, or are not candidates for catheter ablation.
Clinical Trial Considerations
The many unresolved questions and issues regarding currently available clinical trialdata provide a strong incentive for conducting additional clinical studies of specificdesign to answer critical questions in the ablative arena These include: (a) sufficientlypowered, randomized mortality studies; (b) multicenter outcome trials; (c) industry-sponsored device approval studies; and (d) carefully constructed single and multicen-ter registry studies.
Standards for Reporting Outcomes in Clinical Trials
In light of this need, the task force defined 18 specific standards for reporting out-comes in clinical trials of catheter ablation for AF, including the following for whichthere was consensus:
1 A blanking period of 3 months should be employed after ablation when report-ing outcomes.
Trang 343 For research purposes, time to recurrence of AF following ablation is an accept-able endpoint after AF ablation, but may underrepresent true benefit.
4 Freedom from AF at various points following ablation may be a better marker oftrue benefit and should be considered as a secondary endpoint of ablation.5 Atrial flutter and other atrial tachyarrhythmias should be considered treatment
failures.
6 An episode of AF/flutter/tachycardia detected by monitoring should be con-sidered a recurrence if it has a duration of 30 seconds or more.
7 An AF/flutter/tachycardia episode is present if it is documented by ECG andlasts at least 30 seconds.
8 Single procedure success should be reported in all trials of catheter ablation of AF.9 An event monitor should be obtained to screen for recurrent
AF/flutter/tachy-cardia in patients who complain of palpitations during follow-up.
10 Patients being evaluated as part of a clinical trial or in whom warfarin may be dis-continued should have some type of continuous ECG monitoring performed toscreen for asymptomatic AF/flutter/tachycardia.
11 24-hour Holter monitoring is an acceptable minimal monitoring strategy forpatients enrolled in a clinical trial and is recommended at 3- to 6-month inter-vals for 1 to 2 years following ablation.
Conclusion
The Consensus Document on Catheter and Surgical Ablation of AF represents animportant step in the standardization of the field of catheter and surgical ablation of AF.It is hoped that all physicians involved in the care, performance, or follow-up of patientsundergoing catheter or surgical ablation of AF become familiar with this document.
References
1 Calkins H, Brugada J, Packer DL, et al HRS/EHRA/ECAS expert consensus statementon catheter and surgical ablation of atrial fibrillation: recommendations for personnel, pol-icy, 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(6):816–861
2 Fuster V, Ryden LE, Cannom DS, et al ACC/AHA/ESC 2006 guidelines for the manage-ment of patients with atrial fibrillation—a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society ofCardiology Committee for Practice Guidelines (writing committee to revise the 2001
guide-lines for the management of patients with atrial fibrillation) J Am Coll Cardiol 2006;48(4):
149–246.
3 Tracy CM, Akhtar M, DiMarco JP, et al American College of Cardiology/American HeartAssociation 2006 update of the clinical competence statement on invasive electrophysiologystudies, catheter ablation, and cardioversion: a report of the American College of Cardiology/American Heart Association/American College of Physicians Task Force on Clinical
Com-petence and Training developed in collaboration with the Heart Rhythm Society J Am Coll
Cardiol 2006;48(7):1503–1517.
4 Cappato R, Calkins H, Chen SA, et al Worldwide survey on the methods, efficacy, and safety
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David D Spragg
11
I have noticed that after the heart proper, and even the right auricle were ceasing to beatand appeared on the point of death, an obscure movement, ondulation-palpation hadclearly continued in the right auricular blood itself for as long as the blood was percepti-bly imbued with warmth and spirit.
—William Harvey, Exercitatio Anatomica De Motu Cordis et Sanguinis in
Animalibus, 1628
Atrial fibrillation (AF) is the most common sustained tachyarrhythmia encounteredby physicians The prevalence of AF in patients over the age of 65 is approximately6%, and approaches 10% in patients over the age of 85 (1) As the median age of thepopulation in the United States becomes older, the epidemiologic burden of AF inthis country will likely increase Currently approximately 2.2 million people in theUnited States have AF (1) AF, although typically not a life-threatening arrhythmiaper se, is associated with increased risk of stroke (2), heart failure, and increased mor-tality The stroke risk in patients with AF, for instance, is increased between five- andsevenfold compared to similar patients without AF (3,4).
Trang 36in patients with AF, particularly in terms of overall mortality (5,6) However, such astrategy does nothing to reduce the stroke risk and loss of AV synchrony seen inpatients with AF, and as such, represents a suboptimal strategy in many patients.
The second paradigm, rhythm control, has historically involved the use of antiar-rhythmic medications and/or DC cardioversion from AF into sinus rhythm Antiar-rhythmic medications used for the maintenance of sinus rhythm include class I andclass III agents Randomized prospective data have demonstrated that amiodarone,compared to other class III and to class I medications, is the most effective antiar-rhythmic drug to prevent AF (7,8) Long-term therapy with amiodarone is imperfect,however, due both to limited efficacy and to attendant end-organ toxicities Recur-rence rates in patients treated with amiodarone are approximately 35% (7) As impor-tant, amiodarone has dose-dependent effects on thyroid, liver, and pulmonary func-tion In patients treated with DC cardioversion alone (i.e., without the suppressiveeffects of antiarrhythmic medications) AF recurrence is predictably high, with nearly66% of cardioverted patients developing recurrent AF within 15 months (9) In partbecause of the limitations of effective and safe pharmacological therapy for AF sup-pression, clinicians have sought nonpharmacological interventions to achieve rhythmcontrol Two major modalities—surgical intervention and catheter-based interven-tion for the treatment of AF—have developed over the past 25 years The currentchapter reviews these two modalities, with a particular emphasis on the historical evo-lution behind each, and on the seminal discoveries made during that evoevo-lution thatinform our current practices in 2007.
Surgical Treatment for Atrial Fibrillation
In 1959, Moe hypothesized that AF was due to multiple randomly propagating reen-trant waves in the atrium, suggesting that functional reentry was the mechanismunderlying fibrillation (10–12) In subsequent work by Allessie et al (13–15), Moe’shypothesis was confirmed AF was demonstrated to require at least six to eight cir-culating reentrant wavefronts Maintenance of AF depended both on a critical atrialmass and on conduction velocity and refractory periods in the atrial tissue to supportfunctional reentry.
Trang 37The MAZE-III procedure has become the standard by which other surgicalinterventions for AF have been judged Short-, intermediate-, and long-term data areavailable from Cox et al for patients undergoing the MAZE-III (22–24), both forlone AF and in conjunction with other cardiovascular procedures (24) In the 5 yearsbetween 1987 and 1992, 47 patients underwent either the MAZE-I or MAZE-IIprocedure From then until 2000, Cox et al have performed 308 MAZE-III proce-dures Operative mortality for this group was 2.9%, with short-term AF or atrial flut-ter (AFL) recurrence rates of 37% (20) These high recurrence rates, however, werenot indicative of long-term procedure failure Rather, they likely represent atrial irri-tation and changes in atrial electrophysiological properties unique to the postopera-tive period In a review of 8.5 years of follow-up, Cox et al reported a 98% successrate, defined as freedom from any AF (23) Half of the treatment failures by surgeryalone were successfully treated with antiarrhythmic drugs, for an overall cure rate of99% The stroke rate in this population, anticoagulated for the initial postoperativeperiod but then off of systemic anticoagulant therapy, was 0.7% A recent report onthe 15-year follow-up of these patients shows that the results continue to be durable,
with a cure rate of 95% (24).
Despite the high success rates and strikingly low stroke rates in patients under-going the MAZE-III, widespread adoption of the procedure has been limited In partthis has been due to concerns about perioperative sequelae including the need forpermanent pacemaker implantation and the loss of atrial mechanical function Coxet al have reported that up to 15% of patients undergoing the MAZE-III have sub-sequently had pacemakers implanted postoperatively Most of these patients, how-ever, had antecedent sinus node dysfunction that became clinically apparent after ces-sation of AF, rather than acute injury to the AV conduction system during surgery.
Atrial function appears to be preserved in the Cox MAZE-III cohort, with 93%
preservation of biatrial transport function The technically challenging nature of thesurgery, rather than lack of efficacy or attendant complications, appears to be theprincipal factor limiting widespread adoption of the full MAZE-III procedure In1996, Cox et al developed a minimally invasive version of the MAZE (25) This pro-cedure, in which cryoablation is used to form the atrial lesion set through a limitedthoracotomy, has yielded promising short-term results, but does not yet have thelong-term follow-up of the MAZE-III procedure.
Other surgical interventions for AF have been developed (20,26,27) Someare of purely historical interest In 1985, Guiraudon described a unique surgicaltreatment of atrial fibrillation, in which a corridor of intact atrial tissue connectingthe sinus node and the AV junction was isolated (20) Although this procedureallowed for ventricular rate control by the sinus node, it necessarily left the bulkof atrial tissue in fibrillation As such, the corridor procedure did nothing toreduce thromboembolic risk or atrial mechanical dysfunction due to AF, and wasultimately abandoned.
Trang 38The number of randomized clinical trials investigating the efficacy of MAZE-IIIor maze-related procedures is limited Reston et al identified four such trials, inwhich MV surgery in conjunction with AF ablative lesion application was comparedto MV surgery alone (29) They found that restoration of sinus rhythm (81% vs 17%)and prevention of subsequent stroke (0% vs 5.8%) were strongly favored by MAZE-III or maze-related surgery These procedures had no significant impact on overallmortality Pacemaker implantation was higher in patients undergoing AF surgicalintervention than in patients undergoing MV surgery alone (3.9% v 1.5%).
In summary, there has been a 25-year history of surgical intervention for AF Thegold standard for this procedure has been the Cox MAZE-III procedure This inter-vention has demonstrated the virtual elimination of both AF recurrence and long-term stroke incidence The morbidities associated with cardiac surgery, however, andthe complexity of the lesion set has led both surgeons and interventional cardiologiststo investigate other nonpharmacological interventions that approach the treatmentresults of the MAZE-III Catheter-based attempts to recreate the MAZE-III lesionset have evolved over the last 15 years, and form the basis of current endovascularprocedures to treat AF The evolution of these procedures is discussed below.
Catheter-Based Treatment for Atrial Fibrillation
Catheter ablation for atrial tachyarrhythmias is a relatively recent phenomenon(30–35) The propagation of electrical activation from atria to ventricles over myocar-dial fibers was originally described in 1883 (36) Nearly a century later, Scheinman etal described the first catheter-based ablation procedure—His bundle interruption forthe control of ventricular response rates to refractory supraventricular tachycardias(37) Over the last 25 years, catheter ablation techniques have become standard, cur-ative therapy for AVNRT (32), accessory pathway ablation (33,35), and ablation ofmacroreentrant atrial flutter (34) Although ablation of the AV junction has longbeen accepted as a palliative treatment for AF, curative catheter-based therapy hasevolved rapidly since the early 1990s Initial work focused on linear and MAZE-likelesions sets in the right (38,39), right and left (40), and left atria (41) More recently,the importance of AF triggers (particularly those located in the PVs) has been recog-nized and targeted (42)
Linear Ablation Strategies for Treating Atrial Fibrillation
Initial ablation attempts to cure atrial fibrillation focused on linear lesions confined tothe right atrium Between 1994 and 1996, Haissaguerre et al investigated the effectsof linear lesion sets in patients with symptomatic, drug-refractory AF (40) Forty-fiveinitial patients were studied and followed over the long term Patients initially under-went right atrial ablation only, with either a single ablation line from SVC to IVC overthe atrial septum, or multiple lines (longitudinal and transverse) to compartmentalizethe right atrium The procedure led to stable sinus rhythm in 18 of 45 patients (40%)during the procedure Sustained AF was inducible in 40 of 45 patients, however, and19 patients underwent repeat ablation of left- or right-sided atrial flutter or focal atrial
tachycardia After a follow-up period of 11 4 months, only six patients were free of
AF off antiarrhythmic drugs, with another nine patients free of AF on a previously inef-fective medication (overall success of 33%) Nine of 45 patients had significant improve-ment of their symptom burden with the aid of an antiarrhythmic medication, whereasthe remaining 21 of 45 patients had no appreciable effect from RA-only ablation After
Trang 39with seven previous responders (either cure or significant reduction in AF burden)reverting to frequent AF Successful results with RA-only lesions were seen in only 17of 45 patients.
Other investigators have prospectively attempted curative lesion sets confined tothe right atrium Natale et al studied 18 patients with symptomatic, drug-refractory AF(43) Although the lesion sets varied somewhat among the patients (seven with twointercaval lesions, ablation of the cavotricuspid isthmus, and an anterior RA line; 11with a single intercaval line, a septal line, and cavotricuspid isthmus ablation), the results
were generally poor After a follow-up period of 22 11 months, only five of 18
patients remained free from atrial arrhythmia recurrence Most of the 13 recurrencesoccurred within 2 months of the procedure The particular lesion set did not predictprocedure efficacy Thus, although linear ablation confined to the right atrium to cureAF is attractive from a technical and safety standpoint, multiple trials with intermediateand long-term follow-up have shown it to be a largely ineffective procedure (39,44).
Recognizing the limited efficacy of RA-only ablation for AF, several groupsbegan prospective investigations of biatrial and left-atrial linear ablation Haissaguerreet al performed left atrial ablation in 10 of their 45 patients described above (40).Linear ablation in this group terminated AF during the procedure in eight of 10patients In five of 10 patients, sustained AF could not be induced after the proce-dure Intermediate follow-up demonstrated success in six of 10 patients (with twopatients requiring ongoing antiarrhythmic medications).
Between 1996 and 1998, the same group systematically studied biatrial linearablation to cure AF (41) Forty-four patients were enrolled prospectively, the
major-ity of whom suffered from paroxysmal, drug-refractory AF (n 40) Four patients
had persistent AF All patients underwent a similar ablative procedure In the rightatrium, an intercaval septal line and ablation of the cavotricuspid isthmus were made.In the left atrium, linear lesions were applied from the superior PVs to the posteriorMV annulus, including the inferior PV ostia A roof line connecting the two superiorPVs was performed in all patients; a septal left-sided line from the right superior PVto the fossa ovalis was performed in 23 of 44 patients.
This complex lesion set was technically difficult, requiring multiple procedures
(2.7 1.3) and prolonged fluoroscopy (171 94 min) (41) After a follow-up period
of 19 7 months, 25 of the 44 patients were successfully treated, 12 patients were
significantly improved, and seven were without improvement Success rates increasedto 37 of 44 patients with the use of antiarrhythmic medications However, there wereclearly important caveats to the study Only seven of the patients were treated with asingle procedure, whereas the rest were treated with multiple procedures for AF recur-rence, ablation of AF triggers, and/or the ablation of iatrogenic left atrial flutters Per-haps most importantly, triggers of AF arising from the PVs were identified and ablatedin 26 of the 44 patients studied Given the clear importance of trigger elimination incatheter-based cures of AF (discussed below), these results undoubtedly confoundedan analysis of left atrial linear lesions alone as a curative approach to AF Indeed, abla-tion of triggering foci and the creaabla-tion of at least one successful line of block were thetwo sole predictors of success in the 37 patients with a favorable outcome.
Trang 40RA (posterior intercaval, cavotricuspid isthmus, septal) and a single, long linear lesionsurrounding the PV ostia and connecting to the MV annulus in the left atrium Theleft atrial lesion alone was performed in isolation in five patients, wheras the RA lesionset alone was performed in eight patients The success and complication ratesreported by Pappone et al were relatively good, with 16 of 27 patients entirelyasymptomatic from AF (four on antiarrhythmic medications), and another four withmarkedly reduced symptoms No acute complications were reported Successappeared to be predicted by biatrial ablation (85% success vs 50%–60% with single-chamber ablation).
In part because of the limited efficacy of linear ablation alone for AF, and in partbecause of critically important observations by Haisaguerre et al of the triggerednature of AF (discussed below), linear ablation alone for AF is currently not widelyperformed However, observation made by the groups that pursued linear ablation—unmasked triggering foci in patients undergoing linear ablation, and the developmentof simple lesion sets around the PV ostia, in particular—continue to inform currentcatheter-based ablation strategies for AF.
Pulmonary Vein–Targeted Ablation Strategies for Atrial Fibrillation
A seminal event in the catheter-based treatment of AF was the observation by Hais-saguerre et al that fibrillation could be triggered by rapidly firing ectopic atrial foci(42,46,47) In a series of publications in the mid- and late 1990s, Haissaguerre’sgroup reported the successful ablation of AF through radiofrequency ablation offocal trigger points In 1994, they described three patients with atrial tachyarrhyth-mias (46) In the first patient, a focal, rapidly firing atrial tachycardia mimicked AFon ECG, and was successfully ablated The second patient had AT-induced AF, againwith successful ablative therapy targeting the ectopic trigger In the final patient ofthe series, a focal right atrial septal trigger was found and ablated, with markeddiminution of AF burden These initial results were expanded on by a larger series
of patients (n 9), in whom paroxysmal AF was found to be triggered from ectopic
atrial foci (47) In three patients, these foci were located in the RA; in the other six
patients, triggers were at the ostium of the right (n 5) or left (n 1) PVs All
patients underwent successful ablation, with a mean of 4 4 RF applications One
patient suffered an early recurrence of AF and underwent reablation After 10 10
months of follow-up, there were no observed recurrences of AT or AF.
In a larger, landmark study of 45 patients with symptomatic, drug-refractoryparoxysmal AF, Haissaguerre et al reported that all 45 had demonstrable focal atrial
triggers (42) Most patients (n 29) had a single triggering site, although as many
as four triggering sites were observed A total of 69 triggering foci were found, themajority of which (31/69) were located in the left superior PV (LSPV) Other fre-quent sites included the right superior PV (RSPV; 17/69), left inferior PV (LIPV;11/69), and right inferior PV (RIPV; 6/69) Three ectopic foci were located in theRA AF induction was spontaneously observed in 36 patients, and was characterizedby short bursts of two or more repetitive focal firings (40/45 patients) Ablation ofectopic foci was successfully achieved in 38/45 patients Short-term recurrence of AF
was seen in two of the 38 ablated patients After 8 6 months, 28 of the 45 patients
remained free of AF (62%), without the use of antiarrhythmic medications; 17patients, including the early failures, had recurrence of AF.