AFFERA Ventricular Arrhythmia Ablation Registry (AVAAR) — 2025

Authors, Journal, Affiliations, Type, DOI

• Authors: Frédéric Sacher (first author), Andrea Sarkozy, Helmut Pürerfellner, Alexandra Steyer, Jonathan Lyne, Charlène Coquard, Romain Tixier, Nicolas Combes, Michel Haissaguerre, Michalis Efremidis, Josselin Duchateau, Victor Castro Urda, Claire A. Martin, Marc Lemoine, Alejandro Carta Bergaz, Frank Bogun, Nick Linton, Nicolas Derval, Filip Schlosser, Thomas Pambrun, Jan Petru, Meleze Hocini, Luigi Pannone, Martin Mudroch, Josef Kautzner, Pierre Jais, Tobias Reichlin, Petr Neužil, Petr Peichl
• Journal: Europace 2025;27:euaf139; received 25 May 2025, accepted 27 June 2025
• Affiliations: 18 European centres including Bordeaux (LIRYC), Brussels, Linz, Frankfurt (CCB), Dublin, Massy, Toulouse, Athens, Madrid, Cambridge, Hamburg, London, IKEM Prague, Na Homolce Prague, Bern
• Type: Multicentre institutional registry (all European centres using the AFFERA system as of September 2024), non-randomised, no control group
• DOI: 10.1093/europace/euaf139

Overview

The largest systematic dataset for any pulsed-field ventricular ablation platform: every ventricular arrhythmia procedure performed with the AFFERA dual-energy lattice-tip catheter (Sphere-9) at all 18 European centres using the system, 126 patients, minimum 3-month follow-up. It is a safety registry as much as an efficacy study, and it reads like one. Major acute complications occurred in 6% and minor in 14%; 8 patients (6%) had major events between day 1 and 30 including 3 deaths, and the causes are instructive — coronary laceration at epicardial access, progressive heart failure in a patient with LVEF 15%, sepsis. Acute success was 84% and 72% remained free of their arrhythmia at 5.6 ± 3.7 months, with de novo procedures outperforming redo (80% vs 68%). The registry also documents the platform-specific phenomena that matter in practice: coronary spasm with epicardial and RVOT delivery, three cases of haemolysis without renal failure, a catheter-shaft insulation rupture that caused simultaneous VF and AF during RF, electromagnetic interference rendering mapping impossible in two left ventricular assist device patients, and one false tendon avulsed during catheter manipulation.

Keywords

VT ablation; pulsed field ablation; lattice-tip catheter; safety

Key Takeaways

Design and population

• All 18 European centres equipped with the AFFERA system by September 2024 were invited and all accepted; two performed no ventricular ablation during the period. All ventricular arrhythmia ablations until 31 December 2024 were included, with events collected to March 2025 and a minimum follow-up of 3 months. Workflow, imaging, energy mode and application parameters were left to each operator.
• 126 patients, 59 ± 16 years, 18% female. Indication: VT 99, PVC 23, VF 4. Substrate: ischaemic cardiomyopathy 40%, non-ischaemic 46%, no cardiomyopathy 14%; LVEF 37 ± 15% overall (33 ± 12% in the VT group). 64% had ≥1 prior failed ablation, 15% more than three. Three VT patients had prior failed stereotactic body radiotherapy.
• Access: transeptal 65%, retrograde aortic 28%, RV only 11%, epicardial 17% (21 patients, with 40–50 mL intrapericardial saline in 19 to ease manipulation). Energy: PFA only 43%, RF only 15%, both 42%. PFA-only patients received a mean of 39 ± 30 applications (maximum 137); RF-only patients a median 458 ± 307 s.
• Procedure duration 167 ± 57 min (VT 174, VF 210, PVC 128); screening time 12 ± 11 min; general anaesthesia 96%.

Acute complications (procedure to day 1)

• Major 7 (6%): major bleeding 2 (one transfusion, one vascular surgery); tamponade from epicardial access with coronary artery laceration and myocardial infarction 1; cardiogenic shock during prolonged VT mapping requiring CPR and ECMO 1 (recovered); thrombo-embolic events 2; VF induction 1.
• Minor 18 (14%): femoral access 3, atelectasis 1, pericarditis 1, transient ST elevation/depression after application 8, biological haemolysis 3 (no acute kidney injury), mechanical LBBB 1, avulsion of a false tendon during manipulation 1 (no change in mitral regurgitation or LVEF at one year).
• The two strokes were cerebellar, both with full neurological recovery, in patients with LVEF 30–35% undergoing extensive RF + PFA delivery via transeptal access with ACT >350 s and pre-procedural imaging excluding thrombus. Rate 1.6%, within the 0–2.8% reported for standard RF.
• VF and AF induced simultaneously during RF in one patient with an easily inducible slow-pathway AVNRT: electrical noise then induction, traced to a rupture of the shaft insulation on close inspection. Production control and monitoring were instituted and the problem did not recur.
• Coronary effects: direct coronary artery laceration during epicardial access in one (tamponade, infarction, later death). Transient ST changes in eight: five after epicardial PFA (spasm in four, none in one), two after endocardial RV PFA (one RVOT application with subsequent right coronary ostial spasm; one moderator band application with spontaneous normalisation and no spasm), one after endocardial LV PFA with spontaneous resolution and no spasm. All identified spasms resolved with nitrates (1 mg repeated until resolution or hypotension).
• Haemolysis reported in three patients including the one receiving 137 PFA applications, without acute renal failure.
• Electromagnetic interference in both patients with a HeartMate 3 LVAD: the catheter was visible only in the basal ventricle, activation mapping was impossible and ablation tags did not project onto anatomy.

Complications from day 1 to 1 month

• Eight patients (6%). Three deaths: the 75-year-old with coronary laceration (MI, effusion, cardiogenic shock, sepsis); a 57-year-old with ischaemic cardiomyopathy and LVEF 15% who received 76 PFA applications and 6 min RF and died of multi-organ failure after a post-operative day 1 heart failure episode; a 71-year-old with myelofibrosis and valvular cardiomyopathy who died of sepsis with multi-organ failure and tumour lysis/leukostasis.
• Worsening heart failure 2 (day 7 after a transfusion for access bleeding in a patient with LVEF 20%; day 4 in a patient with LVEF 50% after 31 PFA applications and 13.5 min RF over 244 minutes). Myocardial infarction 1 (two weeks later, troponin 800 ng/L, treated by PCI of a venous graft to the marginal branch and judged unrelated). Major gastrointestinal bleeding 1. Sepsis 1.
• One further death at 5 months from VT storm after two more failed ablations; two cardiac transplants (both anticipated before ablation).

Efficacy

• Acute success 106/126 (84%): VT 81/99 (82%), VF 4/4 (100%), PVC 21/23 (91%); 7 undetermined. De novo 87%, redo 83%.
• Absence of recurrence 91/126 (72%) at 5.6 ± 3.7 months: VT 69/99 (70%), VF 4/4 (100%), PVC 18/23 (78%). De novo 36/45 (80%) vs redo 55/81 (68%).

Interpretation offered by the authors

• Major complication rates are comparable to RF ventricular ablation trials in similar populations (3.8–11.2%) and mortality to historical high-risk VT cohorts (in-hospital 0–3%, one-year 3–35%).
• Peri-procedural decompensation has risk factors independent of energy source — prolonged mapping, fluid infusion, fragile patients and general anaesthesia — but the authors specifically warn about cardiac stunning from large PFA fields in scar border zone or healthy tissue, and suggest RF for border-zone work when many applications are required.
• Contact still matters for PFA. Areas recovered on remapping >2 h after application or at redo, and retrospectively lacked the temperature rise that marks an effective application (the system surfaces a temperature trace that distinguishes effective from suboptimal delivery). Repetition is also required — four repetitions produce the deepest lesion in healthy swine. The optimal clinical recipe is not established.
• Mixed RF + PFA permits tailored lesion sets but makes the contribution of each energy uninterpretable; a preclinical study showed sequential colocalised RF and PF — in either order — increases lesion depth and width versus either alone, with central thermal necrosis surrounded by PFA damage.
• No clinical haemolysis consequences were seen, which the authors take as evidence that this system's delivery parameters are relatively safe even with many applications, while noting haemolysis is system-dependent.
• Catheter entrapment is possible: avoid continued rotation in one direction when the catheter is curved near the mitral apparatus.
• Epicardial experience: intrapericardial saline smooths manipulation, tissue was found on the tip after epicardial ablation in one patient (clean before returning endocardially), and the long-term effect of PFA on coronary arteries remains undetermined — swine data show spasm in up to 33% with ventricular endocardial PFA and mild histological change (focal medial fibrosis, intimal hyperplasia) in 18% at one month.

Limitations of the document

• Registry, not a trial. No randomisation, no control group, and all centres using the device were included, introducing centre-level selection and reporting bias; outcomes are compared with historical RF series rather than a concurrent comparator.
• Modest numbers for subgroup analysis despite being the largest series of its kind; the authors state randomised data are required.
• No standardised protocol — imaging, mapping, energy mode, dosing and follow-up varied between centres, so procedural determinants of success cannot be isolated.
• Short follow-up (mean 5.6 months) with no blanking period and no continuous monitoring for all patients; durability and late safety (coronary, renal, autonomic) are unaddressed.
• Mixed-energy population limits attribution of benefit and harm to PFA specifically.
• Safety endpoints are self-reported, and the registry was funded through a national programme with extensive industry relationships among the authors.

Key Concepts Mentioned

• concepts/Ventricular-PFA — modality and biophysics
• concepts/Ventricular-PFA — ventricular application and platform comparison
• concepts/VT-Ablation — procedural risk benchmarks
• concepts/Epicardial-VT-Ablation — epicardial access complications and coronary spasm
• concepts/PVC-Mapping-Ablation — the PVC subgroup
• concepts/VT-Ablation-Ischemic-Cardiomyopathy · concepts/VT-Ablation-Nonischemic-Cardiomyopathy — the dominant substrates
• entities/ICD — the device context for most VT ablation patients

Key Entities Mentioned

• Sphere-9 lattice-tip catheter and AFFERA mapping/ablation system (Medtronic)
• HeartMate 3 left ventricular assist device (Abbott)
• 18 European centres including CHU Bordeaux/LIRYC, UZ Brussel, Ordensklinikum Linz, CCB Frankfurt, IKEM Prague, Na Homolce Prague, Inselspital Bern

Wiki Pages Updated

• Created: wiki/sources/avaar-registry-europace-2025.md
• Updated: wiki/concepts/Ventricular-PFA.md
• Updated: wiki/concepts/Pulsed-Field-Ablation.md, wiki/concepts/VT-Ablation.md, wiki/concepts/Epicardial-VT-Ablation.md
• Updated: wiki/sourceindex.md, wiki/wikiindex.md, log.md