Ablation of atrial fibrillation
Introduction
Ablation therapy is widely used to treat atrial fibrillation (AF), a disease that affects approximately 30 million individuals worldwide [1] and is a major cause of stroke, heart failure, and death. The use of ablation has been encouraged by the disappointing results of important trials that question both pillars of pharmacological therapy—to strictly control ventricular rate [2] and to maintain sinus rhythm [3], [4]. Buoyed by the success of ablation for “simple” supraventricular and ventricular arrhythmias, ablation is increasingly used for AF [5] and is superior to pharmacological therapy for patients with early (paroxysmal) [6], [7] to advanced (persistent) AF [8]. Nevertheless, fibrillation is a complex disease and the overall success of ablation remains lower [9] for AF than for other arrhythmias [6], [7], [10], [11], [12], [13]—despite remarkable successes in individual patients. This has fueled a vibrant culture of intense patient-focused translational research that has characterized the field since its earliest days [14], [15], [16]. This review addresses trends in the field of catheter ablation, focused on defining AF mechanisms and translating them to improved strategies to ultimately improve outcomes in individual patients.
Section snippets
Explaining the diverse trends in AF ablation success rates
The success of AF ablation is widely quoted as 60–80% at 1 year for multiple procedures (average of 1–2) and 40–60% at 1 year for a single procedure [12], [17]. However, these figures mask a remarkable heterogeneity between patients (Fig. 1). The most common approach to AF ablation is pulmonary vein isolation (PVI) to prevent triggers from the pulmonary veins from initiating AF (Fig. 2). However, data consistently show that this uniform procedural goal, applied with the same diligence by
Trends in who to ablate?
Societal guidelines reserve ablation for patients with symptomatic AF [12], and several studies show that ablation in such patients improves quality of life compared to pharmacologic therapy [38], [39], [40]. Nevertheless, this reveals an inconvenient paradox, since success is then measured by eliminating asymptomatic and symptomatic AF. If the results of major ongoing studies ,including CABANA (Clinicaltrials.gov: NCT00911508), CASTLE-AF (Clinicaltrials.gov: NCT00643188), and EAST
Trends in mechanistic understanding to improve ablation of AF
It is generally acknowledged that a better mechanistic understanding of human AF will enable better ablation tailoring to patient-specific mechanisms, i.e., a therapeutically focused functional disease classification. There has been intense investigation into this area in recent years, with several promising advances.
Tachyarrhythmias initiate from a “trigger,” such as a premature beat, and are then maintained by sustaining mechanisms (“substrates”). In AF, the terms trigger and substrate are
Evolving technical aspects of ablation: Less is more
A recent trend is to attempt to limit the amount of tissue destruction during ablation, exemplified by the promise of individualized strategies based on mapping AF [68], [84] that may reduce ablation yet improve long-term outcomes [34].
Nevertheless, there are still patients in whom catheter ablation may not result in long-term freedom from AF. While our understanding of the mechanisms involved in patients with grossly dilated atria and long-standing persistent AF improves, surgical AF ablation
Management of anticoagulation
Minimizing the risk of stroke is a central pillar of AF management, regardless of whether patients are being ablated. Recent landmark trials with the non-vitamin K oral anticoagulants (NOACs) have shifted emphasis away from warfarin [101], although actual prescribing habits vary geographically [102]. Specific challenges of AF ablation in patients using NOACs were the relative lack of data during cardioversion, although recent studies confirm safety [103], and ablation, since it is difficult to
Complications of AF ablation
The specific risks of AF ablation reflect potentially extensive ablation as well as the proximity of atria to adnexae such as the esophagus, phrenic nerves, and other vasculature [105], [106]. Awareness of these risks has improved procedural technique, e.g., eliminating PV stenosis by ablating widely outside PVs (Fig. 2B) instead of close to the thin-walled PVs, while better sheath management and anticoagulation can reduce thromboembolic risk. Accordingly, AF ablation procedural safety has
Conclusions
Ablation for AF is increasingly used because it has been shown to improve maintenance of sinus rhythm compared to drug therapy in numerous multicenter trials. Although success rates remain suboptimal, the remarkable success of ablation in many patients provides a foundation for future advancements. A mechanistic classification of AF will enable better guidance on how to direct ablation in specific populations and should also lead to improved ablation outcomes. Technical advances have improved
References (111)
- et al.
Cardiovascular outcomes in the AFFIRM Trial (Atrial Fibrillation Follow-Up Investigation of Rhythm Management). An assessment of individual antiarrhythmic drug therapies compared with rate control with propensity score-matched analyses
J Am Coll Cardiol
(2011) - et al.
Cryoballoon ablation of pulmonary veins for paroxysmal atrial fibrillation: first results of the North American Arctic Front (STOP AF) pivotal trial
J Am Coll Cardiol
(2013) - et al.
Clinical classifications of atrial fibrillation poorly reflect its temporal persistence: insights from 1,195 patients continuously monitored with implantable devices
J Am Coll Cardiol
(2014) - et al.
Temporal relationship of atrial tachyarrhythmias, cerebrovascular events, and systemic emboli based on stored device data: a subgroup analysis of TRENDS
Heart Rhythm
(2011) - et al.
Atrial remodeling and atrial fibrillation: recent advances and translational perspectives
J Am Coll Cardiol
(2014) - et al.
Catheter ablation for atrial fibrillation: are results maintained at 5 years of follow-up?
J Am Coll Cardiol
(2011) - et al.
Ablation of rotor and focal sources reduces late recurrence of atrial fibrillation compared to trigger ablation alone: extended followup of the CONFIRM (CONventional ablation with or without Focal Impulse and Rotor Modulation) Trial
J Am Coll Cardiol
(2014) - et al.
Effect of catheter ablation on quality of life of patients with paroxysmal atrial fibrillation
Heart Rhythm
(2005) - et al.
Concomitant obstructive sleep apnea increases the recurrence of atrial fibrillation following radiofrequency catheter ablation of atrial fibrillation: clinical impact of continuous positive airway pressure therapy
Heart Rhythm
(2013) - et al.
Impact of metabolic syndrome on procedural outcomes in patients with atrial fibrillation undergoing catheter ablation
J Am Coll Cardiol
(2012)
Biatrial multisite mapping of atrial premature complexes triggering onset of atrial fibrillation
Am J Cardiol
Autonomic denervation added to pulmonary vein isolation for paroxysmal atrial fibrillation: a randomized clinical trial
J Am Coll Cardiol
Randomized comparison of encircling and nonencircling left atrial ablation for chronic atrial fibrillation
Heart Rhythm
Incidence of pulmonary vein conduction recovery in patients without clinical recurrence after ablation of paroxysmal atrial fibrillation: mechanistic implications
Heart Rhythm
Direct or concidental ablation of localized sources may explain the success of atrial fibrillation ablation. On treatment analysis from the CONFIRM Trial
J Am Coll Cardiol
A randomized assessment of the incremental role of ablation of complex fractionated atrial electrograms after antral pulmonary vein isolation for long-lasting persistent atrial fibrillation
J Am Coll Cardiol
A computer model of atrial fibrillation
Am Heart J
Treatment of atrial fibrillation by the ablation of localized sources: the conventional ablation for atrial fibrillation with or without focal impulse and rotor modulation: CONFIRM Trial
J Am Coll Cardiol
Atrial conduction slows immediately before the onset of human atrial fibrillation: a bi-atrial contact mapping study of transitions to atrial fibrillation
J Am Coll Cardiol
Localized rotational activation in the left atrium during human atrial fibrillation: relationship to complex fractionated atrial electrograms and low-voltage zones
Heart Rhythm
Cryoballoon ablation of pulmonary veins for paroxysmal atrial fibrillation: first results of the North American Arctic Front (STOP AF) Pivotal Trial
J Am Coll Cardiol
Phrenic nerve paralysis during cryoballoon ablation for atrial fibrillation: a comparison between the first- and second-generation balloon
Heart Rhythm
European experience of the convergent atrial fibrillation procedure: multicenter outcomes in consecutive patients
J Thorac Cardiovasc Surg
Real-time lesion assessment using a novel combined ultrasound and radiofrequency ablation catheter
Heart Rhythm
Paroxysmal AF Catheter ablation with a contact force sensing catheter: results of the prospective, multicenter SMART-AF Trial
J Am Coll Cardiol
Worldwide epidemiology of atrial fibrillation: a global burden of disease 2010 study
Circulation
Lenient versus strict rate control in patients with atrial fibrillation
N Engl J Med
Rhythm control versus rate control for atrial fibrillation and heart failure
N Engl J Med
In-hospital complications associated with catheter ablation of atrial fibrillation in the United States between 2000 and 2010: analysis of 93 801 procedures
Circulation
Comparison of antiarrhythmic drug therapy and radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation: a randomized controlled trial
J Am Med Assoc
Circumferential pulmonary-vein ablation for chronic atrial fibrillation
N Engl J Med
Caution over use of catheter ablation for atrial fibrillation
Br Med J
Radiofrequency ablation vs antiarrhythmic drugs as first-line treatment of paroxysmal atrial fibrillation (RAAFT-2): a randomized trial
JAMA
Radiofrequency ablation as initial therapy in paroxysmal atrial fibrillation
New Engl J Med
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
Approach to the catheter ablation technique of paroxysmal and persistent atrial fibrillation: a meta-analysis of the randomized controlled trials
J Cardiovasc Electrophysiol
A catheter-based curative approach to atrial fibrillation in humans
Circulation
A focal source of atrial fibrillation treated by discrete radiofrequency ablation
Circulation
Spontaneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary veins
N Engl J Med
Long-term outcomes of catheter ablation of atrial fibrillation: a systematic review and meta-analysis
J Am Heart Assoc
Predictors of recurrence following radiofrequency ablation for persistent atrial fibrillation
Europace
Optimal method and outcomes of catheter ablation of persistent AF: the STARAF 2 Trial
Eur Heart J
ACC/AHA/ESC 2006 guidelines for the management 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 of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients With Atrial Fibrillation): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society
Circulation
Perception of atrial fibrillation before and after radiofrequency catheter ablation: relevance of asymptomatic arrhythmia recurrence
Circulation
A comprehensive evaluation of rhythm monitoring strategies for the detection of atrial fibrillation recurrence: insights from 647 continuously monitored patients and implications for monitoring after therapeutic interventions
Circulation
Long-term progression and outcomes with aging in patients with lone atrial fibrillation: a 30-year follow-up study
Circulation
2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society
J Am Coll Cardiol
Radiofrequency ablation vs antiarrhythmic drugs as first-line treatment of paroxysmal atrial fibrillation (RAAFT-2): a randomized trial
J Am Med Assoc
Subclinical atrial fibrillation and the risk of stroke
N Engl J Med
Cryptogenic stroke and underlying atrial fibrillation
N Engl J Med
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Disclosures: M.W. reports that he has received consulting fees from Philips Healthcare and Biosense-Webster, and participates in educational programs for Biosense-Webster and St. Jude Medical. S.M.N. reports research funding from National Institutes of Health, USA (HL83359, HL122384, and HL103800). S.M.N. is a co-inventor of intellectual property owned by University of California, and licensed to Topera in which he holds equity. He has received consulting fees from the American College of Cardiology, Janssen Pharmaceuticals, and Medtronic.