A novel platform allowing for pulsed field and radiofrequency ablation: First commercial atrial fibrillation ablation procedures worldwide with and without general anesthesia

Abstract

An innovative mapping and ablation catheter (Sphere-9TM, Medtronic) fully integrated into a novel mapping and ablation platform (AfferaTM, Medtronic) was introduced (1Reddy VY, Anter E, Rackauskas G et al. Lattice-Tip Focal Ablation Catheter That Toggles Between Radiofrequency and Pulsed Field Energy to Treat Atrial Fibrillation: A First-in-Human Trial. Circ Arrhythm Electrophysiol. 2020 Jun;13(6):e008718.Google Scholar,2Reddy VY, Peichl P, Anter E et al. A Focal Ablation Catheter Toggling Between Radiofrequency and Pulsed Field Energy to Treat Atrial Fibrillation. JACC Clin Electrophysiol. 2023 Apr 16:S2405-500X(23)00219-0. doi: 10.1016/j.jacep.2023.04.002.Google Scholar). The lattice-tip irrigated catheter has 9 surface mini-electrodes and one central electrode and can toggle between pulsed-field ablation (PFA) and radiofrequency (RF). In the current study patients with symptomatic paroxysmal or persistent atrial fibrillation (AF) received pulmonary vein isolation (PVI) and, if indicated, additional linear lesion sets. All patients gave written informed consent and were included into our prospective TRUST registry (NCT05521451), which was approved by our local ethics committee. Patients were ablated in general anesthesia or under deep sedation using intravenous fentanil, midazolam and propofol. Following single transseptal puncture with a non-steerable transseptal sheath (SL1, Abbott) and selective pulmonary vein (PV) angiography, a 3D bipolar voltage map of the left atrium (LA) and the PVs was generated. PV ostia were tagged according to PV angiographies and local electrical information. PFA-applications of 4 sec. and an inter-lesion distance of 5 mm were set to ablate the PVs. Based on temperature rise at the Sphere-9 surface electrodes lesions are classified adequate if the temperature rises ≥2°C, and inadequate if the temperature rise is <2°C. The tag size is 9mm. In case of inadequate temperature rise, applications were repeated. The system indicates an adequate interlesion distance if there is ≤ 5mm distance from the hottest electrode during one application to the hottest electrode of the following application. Following PVI, another voltage map was generated and PVI confirmed. In case of catheter instability, a steerable sheath (Vizigo™, Biosense Webster) was used. Linear lesions at the posterior LA wall (roof line or posterior wall isolation) were performed with PFA only. Along the anterior wall and the mitral isthmus RF (30W, 4 sec. per application) or PFA was applied at operator`s discretion. The cavotricuspid isthmus (CTI) was targeted applying RF only. A total of 25 patients (64% male, 69 [63, 76] years, 44% paroxysmal, 56% persistent AF) were included with 22 (88%) patients having 4 separate PVs and 3 (12%) with a left common ostium. LA voltage-maps were generated at a mean of 3992±1033 EGMs and a volume of 172±52 ml. 50 pairs of PFA-based ablation lines around the ipsilateral PVs were performed with 100% first pass isolation rate (40±12 applications, 160±48 sec. application time, 15.7±7.3 min ablation time for lateral and 41±14 application, 164±56 sec. and 13.5±6.1 min for septal PVs). Eleven PFA-based roof-lines were bidirectionally blocked at first attempt with 6.5±3.3 applications in 2.2±1.3 min. In 1 patient a posterior box was isolated with PFA and 3 min ablation time. An anterior line connecting the mitral annulus and the right superior PV was ablated and bidirectionally blocked in 6 patients: 2 lines with 17 and 14 RF applications and an ablation duration of 4 and 5 min, and 4 lines by a combination of RF (8.3±6.7 appl.) and PFA (11.5±7.2 appl.) in 7.3±3.2 min (figure). In 3 patients a mitral isthmus line was ablated and blocked: 1 patient RF endocardially only (21 appl., 6 min ablation time), 1 patient PFA endocardially only (5 appl. 2 min ablation time), and 1 patient with RF from endocardially and continued epicardially inside the CS (total 26 appl.) and finally blocked from inside the CS with another 11 PFA-appl. (ablation time 14.7 min). In 5 patients the CTI was bidirectionally blocked with RF only (5.8±1.1 appl. and 1.8±0.4 min ablation time). Mean procedure time and dose area product was 97±24 min and 274±331 cGycm2. Fifteen out of 25 (60%) patients were treated in general anesthesia with muscle relaxant, 3/25 (12%) patients in general anesthesia without muscle relaxant and 7/25 (28%) patients in deep sedation only. Procedures in deep sedation were shorter (89±18 min vs. 99±24 min) without efficacy or safety compromise. No complications occurred in the cohort. In conclusion, catheter ablation with the lattice-tip catheter resulted in successful PVI in all patients. All additional linear lesions beyond PVI were successfully blocked. Procedures were not only performed in general anesthesia but for the first time also in deep sedation in a safe and effective way.

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