Catheter Ablation for Atrial Fibrillation: Indications and Future Perspective

Authors, Journal, Affiliations, Type, DOI

• Authors: Andrea Natale, Sanghamitra Mohanty, Prashanthan Sanders, Elad Anter, Ashok Shah, Ghaliah Al Mohani, Michael Haissaguerre
• Journal: European Heart Journal 2024; 45:4383–4398
• Affiliations: Texas Cardiac Arrhythmia Institute, St. David's Medical Center (Austin, TX); Scripps Clinic (San Diego, CA); University of Adelaide; Shamir Medical Center / Tel Aviv University; Haut–Lévèque Cardiology Hospital (Bordeaux); Alameda Group Hospitals (Cairo)
• Type: State of the Art Review
• DOI: https://doi.org/10.1093/eurheartj/ehae618

Overview

A comprehensive state-of-the-art review by world-leading AF ablation experts covering the full landscape of catheter ablation for AF: the historical discovery of PV triggers, evolving guideline-driven indications, current energy sources and ablation strategies, impact on QOL/cognition/AF progression, and future technology directions. Pulmonary vein isolation (PVI) remains the cornerstone of therapy, with pulsed-field ablation (PFA) emerging as the most significant new technology offering tissue selectivity and an improved safety profile. The 2023 ACC/AHA/HRS guidelines upgraded catheter ablation to Class I in AF+HFrEF for the first time.

Keywords

Atrial fibrillation, catheter ablation, pulsed-field ablation, quality of life, cognition, AF progression

Key Takeaways

Background

• AF defined by uncoordinated atrial activation with ineffective atrial contraction; increases risk of stroke, HF, and mortality (near doubling of mortality as an independent predictor, even in patients free of baseline MI, CHF, valvular disease, and stroke/TIA)
• Ectopic triggers from veno-atrial junctions or arrhythmogenic atrial tissue initiate AF; may be automatic or re-entry-driven
• Blood stasis in fibrillating atria promotes thromboembolic complications; AF is also a common cause of tachycardia-induced cardiomyopathy (LV systolic dysfunction via tachycardia, irregular rhythm, dyssynchrony)
• Main aim of therapy: achieve stable sinus rhythm to reduce complications and improve QOL

History of AF Ablation

• 1994: Swartz et al. first reported RF Maze-like lesion sets percutaneously; Haissaguerre et al. described focal sources (SVC, right atrium) triggering AF; left atrial lines in 45 patients showed 56% improvement vs 11% with right atrial ablation alone
• 1998 landmark (NEJM): Haissaguerre et al. identified PVs as the source of 65/69 ectopic foci (94%) responsible for spontaneous AF initiation — established PVI as the cornerstone of therapy

• 11,000 publications on AF ablation in the last two decades

• ~80% of UK Biobank participants diagnosed with AF were eligible for early rhythm control

Indications for Catheter Ablation

• Class I/A (universal): AF ablation in drug-refractory symptomatic PAF patients seeking rhythm control; supported by RAAFT, RAAFT-2, MANTRA-PAF, STOP-AF, EARLY-AF, CRYO-FIRST trials
• First-line in selected PAF: Recommended for younger patients with fewer comorbidities; ablation preferred as first-line over AAD in this group
• Repeat ablation (Class I): Both ESC 2020 and ACC/AHA 2023 guidelines; ~30–40% of patients experience recurrence after first ablation
• AF + HF:
  • AATAC: ablation superior to amiodarone in persistent AF + HF (EF <40%) for AF-free survival, hospitalisation, and mortality
  • CASTLE-AF: significantly lower all-cause mortality and HF hospitalization in EF <35% with ablation vs medical therapy
  • CABANA HF substudy: catheter ablation produced clinically important improvements in survival, AF-free survival, and QOL in stable HF patients
  • RAFT-AF (high-burden AF + HF vs rate control): no mortality difference, but substantial QOL improvement, improved EF, 6MWT, NT-proBNP in ablation group
  • CASTLE-HTx (end-stage HF): ablation + GDMT associated with lower composite of death/LVAD/urgent transplant vs medical therapy alone
  • 2023 guidelines (first time): Class I for catheter ablation in AF + HFrEF
• Class IIa: Symptomatic persistent AF, early-onset AF (<45 years), first-line in all PAF, tachycardia-bradycardia syndrome, athletes, asymptomatic/minimally symptomatic PAF or persistent AF
• LSPAF: Class IIa (2017 consensus); empirical LAA isolation in LSPAF improves long-term arrhythmia freedom (BELIEF trial)
• Not recommended: Severe pulmonary hypertension at baseline; asymptomatic LSPAF

Evolving Indications for Rhythm Control

• EAST-AFNET 4: Early rhythm control within 12 months of AF diagnosis reduces CV death, stroke, and HF hospitalization; benefit requires sinus rhythm to be present at 12 months — no benefit if AF persists despite therapy
• Meta-analysis of 8 studies (n=447,202): Early rhythm control (drug/ablation) associated with improved outcomes in newly diagnosed AF
• Early rhythm control equally effective in symptomatic and asymptomatic patients per recent RCT data
• ESC 2024: Post-ablation blanking period shortened to 8 weeks (previously 3 months)
• Ongoing: CABA-HFpEF (NCT05508256), EASThigh-AFNET 11 (NCT06324188), TAP-CHF (NCT04160000)

Energy Sources

Radiofrequency vs. Cryoballoon Ablation

• FIRE and ICE trial: Cryoablation equivalent in safety and non-inferior in efficacy to RF for drug-refractory PAF
• Meta-analysis of 6 RCTs: CB2 and CF-RF equivalent for arrhythmia freedom and complications; CB2 shorter procedure time but higher phrenic nerve palsy incidence
• Same equivalence findings reported in persistent AF
• POTTER-AF registry: Oesophageal fistula more prevalent with RF than cryoenergy
• Choice of modality may influence AF progression: CF-guided RF ablation 0% PAF→persistent AF progression vs 7% (cryo 4 min) and 4.3% (cryo 2 min) in one multi-centre RCT (P=0.03)

Contact Force-Guided RF Ablation

• Average CF >10 g with ≥80% ablation time within selected CF range optimises arrhythmia control
• High CF >20 g associated with serious complications: atrioesophageal fistula, steam-pops, pericardial tamponade

High-Power Short-Duration (HPSD) Ablation

• 45–50 W for 2–10 s: effective with low complication rates and significantly shorter procedure times
• LAPW adjacent to oesophagus: HPSD ≤5 s inadequate for durable lesions; strategies to displace the oesophagus are required
• Associated with very low incidence of silent cerebral embolism (comparable to conventional approach)
• New HPSD tools: DiamondTemp catheter, Sphere9 lattice electrode tip, QDOT micro catheter

Ultralow Temperature Cryoablation (ULTC)

• Novel ADAGIO system uses near-critical nitrogen at −196°C to create deeper lesions than conventional cryoenergy
• FDA trial ongoing for ULTC PVI and posterior wall ablation in persistent AF

Pulsed-Field Ablation (PFA)

• Non-thermal, electroporation-based energy; tissue-selective — spares oesophagus, phrenic nerve, PV walls
• Advantages: tissue selectivity, no coagulative necrosis (no PV stenosis), ultra-rapid application, not contact-force dependent
• ADVENT trial: PFA non-inferior to conventional thermal ablation for freedom from recurrence, AAD use, cardioversion or repeat ablation, and serious adverse events in PAF
• PULSED AF and PersAFOne: safety and efficacy in both PAF and persistent AF; LAPW ablation feasible
• European real-world data: safe and effective in all-comer AF population for PVI + extra-PV lesions
• MANIFEST-PF retrospective registry: adjunctive LAPWI not beneficial at 12 months (but criticised: small sample 131 patients/24 centres, unverified durability, variable monitoring)
• Coronary vasospasm: risk adjacent to coronary artery; effectively attenuated by prophylactic nitroglycerin
• Acute kidney injury (AKI): from intravascular haemolysis; dose-dependent on PFA application count; preventable by planned peri-procedural fluid infusion
• Prevents pulmonary hypertension worsening compared with RF in AF + stiff left atrial syndrome
• No PV stenosis, oesophageal injury, or phrenic nerve damage reported
• Thromboembolic events: TIA 0.8% (IMPULSE/PEFCAT I/II); stroke 0.39%, TIA 0.11% (MANIFEST-PF); most MRI cerebral lesions transient (97% normal MRI at 40-day follow-up in one series)

Ablation Strategies

Antral vs. Ostial PVI

• Antral PVI encompasses wider area including part of LAPW; meta-analysis (1183 patients): antral approach significantly more effective than ostial PVI for long-term arrhythmia freedom with RF ablation
• With PFA: antral approach associated with less re-ablation; ostial PFA patients more frequently required repeat procedures

Left Atrial Posterior Wall Isolation (LAPWI)

• Frequently used adjunctive technique to improve efficacy in persistent AF
• CAPLA RCT: failed to show benefit of LAPWI in ablation-naïve persistent AF patients
• Meta-analysis of 8 RCTs: significant reduction in AF recurrence in persistent AF with additional LAPWI vs PVI + roof line
• Discordance attributed to patient selection (early persistent AF responds well to PVI alone, similar to PAF), failure to create transmural lesions, and variation in technique (box lesion vs. point-by-point)
• Triggers from lower posterior wall (below inferior PV line) can cause recurrence if not targeted
• Septopulmonary bundle (SPB): subepicardial fibres creating epicardial conduction gaps during roof-line ablation — key obstacle to durable LAPWI

Non-PV Triggers

• Common sites: LAPW, SVC, coronary sinus (CS), crista terminalis, interatrial septum, LAA
• More prevalent in: non-PAF, female sex, obesity, sleep apnoea, older age, low LVEF, severe LA scarring, HCM, mechanical mitral valve
• SVC, LAA, CS: complete isolation preferred (not focal ablation)
• LAA triggers: present in 27% of consecutive series (987 patients); BELIEF trial: empirical LAA isolation improved long-term arrhythmia freedom in LSPAF (but limited by small sample size and operator variability)
• LAA isolation: significant stroke risk — requires uninterrupted anticoagulation or LAA occlusion device

Redo Ablation Targets

• PV reconnection historically the main cause of recurrence; less common with contemporary ablation technologies
• Many patients experience recurrence despite durable PVI; optimal redo targets beyond PVI are an evolving area
• Very late recurrence in PAF with permanently isolated PVs: non-PV triggers (CS, LAA) responsible
• After multiple failed PVI: non-PV triggers responsible in majority; adjunctive isolation of SVC, LAA, CS provides high arrhythmia-free survival

Vein of Marshall (VOM) Ethanol Infusion

• Effective for bidirectional mitral isthmus block in perimitral flutter (Marshall-PLAN strategy)
• VENUS trial: better outcome in persistent AF with catheter ablation + VOM ethanol vs ablation alone
• Limitations: technically complex, frequent procedural failures; absolute benefit in as-treated analysis only 14%

Ganglionated Plexi (GP) Ablation

• GPs play a role in AF initiation and maintenance; endocardial access limited by association with great vessels
• GANGLIA-AF RCT: GP ablation alone no better than PVI alone for preventing atrial arrhythmias

Adjunctive Renal Denervation (RDN)

• ERADICATE-AF (PAF + hypertension): RDN added to catheter ablation significantly increased AF freedom at 12 months vs ablation alone
• RDN+AF study: no benefit of RDN in AF patients with multidrug-resistant hypertension
• Optimal patient selection, timing, and durability unresolved

AF Mapping-Guided Ablation

• Topera system (Abbott): failed in randomized multi-centre trial
• CardioInsight non-invasive body surface mapping (AFACART): 78% AF-free at 1 year, but 50% developed atrial tachycardia
• Ablacon EGF (FLOW AF, 85 patients): PVI + EGF-guided source ablation 68% arrhythmia-free vs 17% with repeat PVI only
• Volta Medical AI (50 persistent AF patients): 48% free from arrhythmia at 1 year post-single procedure; 82% in sinus rhythm after average 1.46 procedures; TAILOR-AF RCT (NCT05169320) ongoing
• Barriers: no universal electrogram recording standard, low spatial resolution, unstable drivers/rotors, reliance on automated algorithms

Quality of Life, Cognition, and AF Progression

Quality of Life

• Multiple small RCTs, CABANA trial (n=2204, RF ablation vs medical therapy): significant improvement in QOL (AFEQT score and Mayo AF symptom inventory) at 12 months, sustained over time, irrespective of AF recurrence
• STOP-AF, EARLY-AF, Cryo-FIRST trials: substantial QOL improvement with cryoablation
• PFA: similarly reduces AF burden and improves QOL with lower healthcare utilisation

Cognition and Dementia Prevention

• Meta-analysis (15,886 ablated vs 42,684 medically managed): HR 0.60 for incident dementia (95% CI 0.42–0.88; P<0.05)
• AF independently increases dementia/cognitive decline risk with or without clinical stroke; association stronger in younger patients and longer AF duration
• Proposed mechanisms: silent cerebral infarct, altered cerebral perfusion, vascular inflammation
• Acute MRI-detected cerebral lesions post-ablation: frequent peri-procedurally, but transient — full recovery within 12 months

AF Progression

• EARLY-AF (NEJM 2023): cryoablation as first-line reduced PAF → persistent AF progression from 7.4% (AAD arm) to 1.9% (ablation arm) at long-term follow-up
• 'AF begets AF' paradigm: AF-induced cardiac remodelling perpetuates progression from paroxysmal to persistent forms
• Multi-centre RCT: RF ablation 0% vs cryoablation 4.3–7% PAF progression, suggesting modality choice matters
• AF ablation guideline upgrade to Class I first-line in PAF driven in part by this progression prevention data

Future Perspectives

• AF mapping: AI-enhanced technologies (Volta Medical, Ablacon EGF, Acutus charge density mapping) show early promise; no universal recording standard; TAILOR-AF RCT pending
• Virtual atrial modelling: Patient-specific LGE-MRI fibrosis models simulate and plan ablation strategies; in silico approach RCT (108 patients) did not improve over standard care; fibrosis treated uniformly despite its heterogeneous nature — a key limitation
• PFA refinement: Longer-term safety data needed; optimal adjunctive ablation beyond PVI in persistent AF requires RCT evaluation; need to reduce AKI and coronary vasospasm
• Ongoing outcome trials: CABA-HFpEF, TAP-CHF, EASThigh-AFNET 11

Limitations of the Document

• Review article; randomized trials include selective patients; findings need real-world validation in large AF registries
• Safety and efficacy data predominantly from high-volume experienced centres; unclear generalisability to low-volume centres
• Voluntary registry data subject to reporting bias; adding complications from claims data recommended
• Safety and efficacy of AF ablation in elderly patients understudied

Key Concepts Mentioned

• concepts/Catheter-Ablation-AF — main subject of review
• concepts/Pulsed-Field-Ablation — major emerging ablation technology
• concepts/AF-CARE — broader AF management framework
• concepts/CHA2DS2-VA — stroke risk scoring referenced in anticoagulation context
• concepts/AF-Staging — classification used to guide ablation decisions

Key Entities Mentioned

• entities/Atrial-Fibrillation — primary disease entity
• entities/Atrial-Flutter — related arrhythmia; perimitral flutter mentioned in VOM section

Wiki Pages Updated

• wiki/sources/ca-af-ehj-2024.md (this page, created)
• wiki/concepts/Catheter-Ablation-AF.md (updated: energy sources, ablation strategies, QOL/cognition/AF progression sections)
• wiki/concepts/Pulsed-Field-Ablation.md (created)
• wiki/entities/Atrial-Fibrillation.md (updated: AF progression data, cognitive protection)
• wiki/wikiindex.md (updated)
• log.md (updated)