Heart Rhythm 2024: SPHERE PER AF Study

Live from the Heart Rhythm 2024 conference

First international randomized study comparing the Sphere 9 catheter to a standard RF catheter for persistent AF: a revolution?

Key messages

• Sphere-9 catheter (AFFERA) sphere-shaped, deformable mesh allowing mapping and ablation by electroporation or radiofrequency
• First international randomized study comparing it to a standard catheter to treat persistent AF
• The Sphere 9 was shown to be non-inferior in terms of safety and efficiency but allowed procedure times to be 20% shorter.

Introduction

We are at a pivotal moment in our specialty with a technological leap moving from radiofrequency to electroporation. All companies come up with solutions which have different efficiency/security profiles from each other and which must therefore be evaluated.

This study evaluates the SPhere 9 solution (Affera) which delivers electroporation and radiofrequency.

Methodology and results

Population

Classic of patients benefiting from ablation of persistent AF (67 years old; mean LA diameter 44 mm; mean Chads-vascular score: 2.4) with 212 patients randomized Sphere 9 and 208 Thermocool

Design

Single-blind, multicenter, randomized study evaluating the non-inferiority of the Sphere 9 solution vs. a standard radiofrequency ablation solution.

Judgment criteria

• Main effectiveness criterion: composite criterion requiring the absence of the following 3 criteria:
  • Failure to isolate pulmonary veins with the specified catheter
  • Recurrence of AF/TA/Atrial Flutter (>30 seconds) after the 90-day blanking period
  • Initiation or increase in doses of class I/III antiarrhythmics

Main safety criterion : incidence of pre-specified adverse reactions related to the catheter or procedure.

Secondary criteria

• Superiority on the effectiveness criterion
• Efficiency (ablation and procedure time)
• Quality of life
• Assessment of silent brain lesions by brain MRI

Main result

Rate of maintenance in sinus rhythm at one year: 73.5% in the Sphere 9 arm vs. 65.2% in the Thermocool arm, (non-inferiority p

Adverse event rate: 1.4% in the Sphere 9 arm vs. 1% in the Thermocool arm

Secondary endpoint results

• Non-significance of the superiority criterion
• Efficiency: ablation time 7 vs 36 min (p
• Evaluation of silent brain lesions by brain MRI: Hyperintensity in FLAIR sequence at 3 months: 2.7 vs 2.9% (NS)

Figure 1 *^{Image from Dr Elad Anter’s presentation at the HRS 2024 LBT}

Conclusion

Each electroporation system arriving on the market will have to prove its effectiveness/safety profile. That of sphere 9 seems particularly good.

Reference

^{Dual-energy lattice-tip ablation system for persistent atrial fibrillation: a randomized trial.
Anter E, Mansour M, Nair DG, Sharma D, Taigen TL, Neuzil P, Kiehl EL, Kautzner J, Osorio J, Mountantonakis S, Natale A, Hummel JD, Amin AK, Siddiqui UR, Harlev D, Hultz P, Liu S , Onal B, Tarakji KG, Reddy VY; SPHERE PER-AF Investigators. Nat Med. 2024 May 17. doi: 10.1038/s41591-024-03022-6}

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