All-in-one PFA system linked to positive safety profile, faster procedures
Devi G. Nair, MD, director of cardiac electrophysiology and the Arrhythmia Research Group at St. Bernard's Heart and Vascular Center and an assistant professor with the University of Arkansas for Medical Sciences, discussed her experience using the Medtronic Sphere-9 second-generation pulsed field ablation (PFA) system for the treatment of persistent atrial fibrillation (AFib) at the Heart Rhythm Society (HRS) 2024 meeting.
The novel Medtronic Affera Mapping and Ablation System with the Sphere-9 catheter is designed as both a high-density mapping catheter and an ablation system using one catheter and eliminating exchanges. Its ball shape is designed to be used for single-shot pulmonary vein isolation using PFA. The concept of the system its to speed up ablation procedures while improving safety with PFA. The data show it was a more efficient system with faster procedure times.
"The persistent AFib population is a hard population to treat. And the trial looked at randomizing patients to the control group, which was ThermoCool SF. That's a catheter we have used for a very long time and we're really good at it now. So we were comparing a brand new mapping system and a brand new catheter to something that we were very comfortable with. As an investigator, I was going to be a huge learning curve. And I was just surprised by how quick the learning curve was. It was a very intuitive ... it was very efficient and easy to learn," Nair explained.
The trial compared the all-in-one Sphere-9 to the Thermocool SmartTouch SF radiofrequency ablation focal ablation treatment with the Carto mapping system, a commonly used focal ablation treatment. It included 420 patients enrolled across 23 sites in the United States, Czech Republic and Israel. All patients in both arms of the trial received pulmonary vein isolation as well as linear lesions based on the patient's needs. The results showed the new system was noninferior to the SmartTouch SF. It also excelled in some areas.
The Sphere-9 demonstrated a positive safety profile with an excellent primary safety endpoint rate of 1.4% (1% for the control arm). No safety events including pulmonary vein stenosis, esophageal events or cardiac tamponade were reported. More than 95% of Sphere-9 procedures used a single transeptal puncture, compared to 62% in the control arm.
Sphere-9 demonstrated 73.8% freedom from AFib vs. only 65.8% observed in the control arm. Following 100% acute isolation of pulmonary veins and linear lesions, patients treated with the Sphere-9 catheter also observed less recurrence of atrial arrhythmias throughout the 12-month follow up period.
Treatment with the Sphere-9 catheter demonstrated superior efficiency over the control arm for procedural characteristics, including skin-to-skin procedural time, time between first and last ablation and energy application time.
"What stood out to me were some of the secondary analysis, which was the efficiency aspects like skin-to-skin time, the time it took from the first lesion to the last lesion, or the total energy application time. All of this was superior in the Sphere-9 catheter, which tells you that whole concept of an all-in-one catheter, having no exchanges, being able to map with it, ablate with it, validate with it and get out. And to me, that's huge. So I think 95% of operators in the trial in the Sphere-9 side did not exchange the catheter. With the control group, it was zero," Nair explained.
PFA is rapidly changing EP practice. Nair said all of her de novo ablations are now done with PFA. If a patient comes back for a redo ablation, they map it and the decide between PFA and RF.
The data from the study was simultaneously published in Nature Medicine.
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: dfornell@innovatehealthcare.com