Scientific publications for cardiac ablation solutions
Sphere-9™ mapping and ablation catheter for ventricular tachycardia
Summary
- The U.S. commercial Affera™ mapping and ablation system and ablation settings (PULSE3, RF-ANT, and RF-MI) with the Sphere-9™ mapping and ablation catheter were designed and approved for atrial tissue. Reports of cases, in literature or conferences, demonstrating the use of the Affera™ system to treat ventricular arrhythmias were performed on systems that are different from what was approved by the FDA and commercially available in the United States.
- Through preclinical research, ventricular settings (PULSE3V and longer modified radiofrequency [RF]) have been created and are actively being studied in an ongoing feasibility study with a pivotal trial to follow.
- FDA-approved “compassionate use“ provides a pathway to access the investigational ventricular settings.
Articles of interest
Medtronic summary
- Prospective observational study of 18 subjects, all failed prior ventricular ablations
- Post-ablation non-inducibility was achieved in 89% (16/18) and 78% freedom from ventricular arrhythmia at three months
- One stroke reported with resolution at one month
- Close proximity to coronary artery led to spasm during epicardial ablation, all resolved with intracoronary nitroglycerin
Peichl P, Wichterle D, Schlosser F, Stojadinović P, Nejedlo V, Borišincová E, Marek J, Štiavnický P, Hašková J, Kautzner J. Mapping and ablation of ventricular tachycardia using dual-energy lattice-tip focal catheter: early feasibility and safety study. Europace. 2024:euae275. doi:10.1093/europace/euae275.
Disclosures: Josef Kautzner reports personal fees from Medtronic for participation in scientific advisory boards and has received speaker honoraria from Medtronic. Vojtěch Nejedlo is an employee of Medtronic. The remaining authors have no disclosures.
Medtronic summary
- Compassionate use case, 74-year-old male with prior MI, severe coronary artery disease (CAD), and multiple failed RF ablations at multiple institutions
- Mapping revealed diffuse breakout pattern at the inferolateral border of the scar with centripetal activation.
- 60-second RF applications resulted in late termination, nonsustained runs remained. Repetitive pulsed field ablation (PFA) applications with PULSE3V was applied at the site of termination rendering the ventricular tachycardia (VT) noninducible.
- Patient remained free from VT recurrence at the four-month follow-up.
Aguilera J, Obeng-Gyimah E, Kuramochi Y, Chung R, Cochet H, Christie M, Nakagawa H, Sroubek J, Wazni O, Santangeli P. Elimination of epicardial scar-related ventricular tachycardia with endocardial pulsed field ablation: first clinical report. Circ Arrhythm Electrophysiol. 2024;17(10):e012992. doi:10.1161/CIRCEP.124.012992.
Disclosures: Pasquale Santangeli and Oussama Wazni have received research grants and consultancy fees from Medtronic.
Medtronic summary
- Multiple failed prior VT ablations (endocardial and epicardial)
- Epicardial VT exit adjacent to left circumflex (LCx), isosorbide dinitrate administered to manage spasm
- Epicardial PFA targeted and eliminated all local abnormal ventricular activity (LAVA) at basal left ventricle (LV)
- VT noninducible with up to three extrastimuli and no VT recurrence after three-month follow-up
Yokoyama M, Vlachos K, Duchateau J, Sacher F, Jaïs P, Tixier R. Pulsed field epicardial ablation for VT storm: a case report of bailout therapy. Heart Rhythm. 2024:S1547–5271(24)03140-0. doi:10.1016/j.hrthm.2024.08.021.
Disclosures: The authors have no conflicts of interest to disclose.
Medtronic summary
- Four VT patients of differing etiologies were treated and followed
- RF and pulsed field (PF) delivered at operator’s discretion, PF-first in the right ventricle (RV) and RF-first in the LV
- All procedural endpoints based on patient presentation and successfully met; no recurrences observed over a median follow-up of five months
- No procedural complications observed acutely or during follow-up
Pannone L, Doundoulakis I, Cespón-Fernández M, Eltsov I, Chierchia GB, de Asmundis C, Sarkozy A. A large footprint focal catheter toggling between pulsed field and radiofrequency energy: first clinical experience for ventricular tachycardia ablation. Europace. 2024;26(7):euae193. doi:10.1093/europace/euae193.
Disclosures: Gian Battista Chierchia received compensation for teaching purposes and proctoring from Medtronic. Carlo de Asmundis receives research grants on behalf of the centre from Medtronic; Carlo de Asmundis received compensation for teaching purposes and proctoring from Medtronic. The remaining authors have nothing to disclose.
Medtronic summary
- Compassionate use case, 48-year-old male with an extensive VT history and failed ablations
- Mapping localized earliest activation to be the left ventricular His-left bundle branch region as the site of a micro re-entrant circuit
- An abbreviated PF application delivered to confirm effect on arrhythmia and conduction; VT terminated with RF at the site and RF used to consolidate the boundary away from the conduction system
- At six months, no sustained VT and a reduction in premature ventricular contraction (PVC) burden observed
Nies M, Koruth JS, Musikantow DR, Watanabe K, Kawamura I, Malyshev Y, Maan A, Reddy VY. Pulsed field mapping of ventricular tachycardia: verifying the ablation target at a critical location. JACC Clin Electrophysiol. 2024;10(3):630–636. doi:10.1016/j.jacep.2023.12.005.
Disclosures: Jacob S. Koruth has served as a consultant for Medtronic; has received grant support and stock options from Affera-Medtronic; Vivek Y. Reddy has served as a consultant to and received equity from Affera-Medtronic; Vivek Y. Reddy unrelated to this manuscript he also serves as a consultant for and has equity in Epix Therapeutics-Medtronic and has served as a consultant for Medtronic. All other authors reported that they have no relationships relevant to the contents of this paper to disclose.
Medtronic summary
- In vivo infarcted swine model used to evaluate lesion formation of PFA (repetitive PULSE3V) against conventional RF ablation (30 W, 10–20 g, and AI 700–900)
- No muscle stimulation or sustained ventricular arrhythmias reported with PULSE3V; 26.7% (4/15) of RF applications resulted in sustained VAs
- All morphology measurements (depth, width, percentage of wall depth) and transmurality significantly greater in the PF cohort compared the to the RF cohort
- Lesion dimensions (depth and width) for PFA versus RF: 6.4 mm [5.5–7.5] and 16.5 mm ± 1.8 mm versus 5.4 mm [4.8–5.9] and 9.9 mm ± 1.7 mm, respectively
Younis A, Zilberman I, Krywanczyk A, Higuchi K, Yavin HD, Sroubek J, Anter E. Effect of pulsed-field and radiofrequency ablation on heterogeneous ventricular scar in a swine model of healed myocardial infarction. Circ Arrhythm Electrophysiol. 2022;15(10):e011209. doi:10.1161/CIRCEP.122.011209.
Disclosures: Elad Anter receives research grants, speaking honoraria, and holds stock options from Affera, Inc. The other authors report no conflicts.
Medtronic summary
- A series of experiments assessing catheter performance and lesion dimensions from PFA delivered in a healthy and infarct in vivo swine model
- PULSE3V (ventricular setting) delivered epicardially with 24.6 ± 9.7, 15.6 ± 4.6, and 4.5 ± 3.7 mm dimensions (L, D, W respectively)
- Epicardial fat (<4 mm) did not significantly attenuate lesion depth
- PULSE3 (atrial setting) induced ventricular fibrillation (VF) in three of 81 applications delivered at the scar border
Kawamura I, Reddy VY, Wang BJ, Dukkipati SR, Chaudhry HW, Santos-Gallego CG, Koruth JS. Pulsed field ablation of the porcine ventricle using a focal lattice-tip catheter. Circ Arrhythm Electrophysiol. 2022;15(9):e011120. doi:10.1161/CIRCEP.122.011120.
Sources of funding: This study was supported by a research grant from Affera, Inc.
Disclosures: Vivek Y. Reddy and Jacob S. Koruth have received research grants and hold stock options from Affera, Inc. The other authors report no conflicts. Additionally, Vivek Y. Reddy disclosures with medical companies (unrelated to this manuscript) include: Epix Therapeutics (Consultant, Equity), Medtronic (Consultant).
Medtronic summary
- In vivo swine model was used to assess acute and chronic lesion formation from single or repetitive (four times) PFA applications
- PFA exhibited repetition dependency as lesion dimensions increased with consecutive applications
- Acute lesion dimensions (depth and width) for single versus repetitive PFA applications: 5.6 mm ± 1.43 mm versus 8.8 mm ± 0.74 mm and 17.2 mm ± 2.9 mm versus 22.7 mm ± 2.3 mm, respectively
- Chronic lesion dimensions (depth and width) for single versus repetitive PFA applications: 3.3 mm ± 0.92 mm versus 7.3 mm ± 0.83 mm and 18.3 mm ± 3.9 mm versus 24.3 mm ± 2.8 mm, respectively
Yavin HD, Higuchi K, Sroubek J, Younis A, Zilberman I, Anter E. Pulsed-field ablation in ventricular myocardium using a focal catheter: the impact of application repetition on lesion dimensions. Circ Arrhythm Electrophysiol. 2021;14(9):e010375. doi:10.1161/CIRCEP.121.010375.
Sources of funding: The study was partially funded by Affera, Inc.
Disclosures: EA receives research grants, speaking honoraria, and holds stock options from Affera, Inc. The other authors report no conflicts.
Considerations associated with the use of the Sphere-9™ catheter for the treatment of VT
Indications
The FDA-approved use for the Sphere-9™ catheter is indicated for use in cardiac electrophysiological mapping (stimulation and electrogram recording) and for treatment of drug refractory, recurrent, symptomatic persistent atrial fibrillation (episode duration less than one year), and radiofrequency ablation of cavotricuspid isthmus dependent atrial flutter when used with the Affera™ mapping system.
The Affera™ mapping system is intended to be used for catheter-based cardiac electrophysiological mapping. The mapping system allows pacing and real-time visualization of compatible catheters as well as display of cardiac maps in multiple formats. The acquired patient signals, including intracardiac electrograms, may also be recorded and displayed on the system’s display screen.
Contraindications
- In coronary vessels with diameter smaller than the expandable ablation electrode, as the catheter may damage the coronary vessels
- In patients with prosthetic valves, as the catheter may damage the prosthesis
- Using the retrograde approach in patients who have had aortic valve replacement
Warning and precautions
- Cardiac ablation may induce intentional or unintentional life-threatening cardiac arrhythmias. Defibrillation equipment must be available for immediate use in the case of a life-threatening arrhythmia.
- Carefully observe the recommended settings in the instructions for use to reduce the risk of delivering excessive energy causing excessive heating or collateral damage. Excessive ablation duration may also lead to excessive heating or collateral damage.
- PF ablation in areas adjacent to coronary arteries may lead to coronary artery spasm.
Potential adverse events
- Hemodynamic decompensation/cardiogenic shock
- Epicardial access complications (e.g., inadvertent right ventricular puncture, diaphragmatic puncture, hemopericardium, pneumopericardium, vascular puncture)
- Esophageal fistula