One of the biggest technology trends in cardiac electrophysiology is the the development of pulsed field ablation (PFA), a non-thermal ablation treatment for patients with atrial fibrillation (AF). The Heart Rhythm Society (HRS) included three positive late-breaking clinical studies at its Heart Rhythm 2023 meeting in May that may help pave the way for PFA to become one of the biggest advancements in ablation therapy.
The advantage of the new therapy is that it uses electrical fields to cause electroporation, where holes open up in the walls of the heart cells being targeted, leading to cell death to stop dangerous cardiac arrhythmias. Experts in the electrophysiology (EP) field say this is an improvement over traditional radio frequency (RF) ablation that heats tissue, or cryoablation that freezes tissue, to kill cardiomyocytes that are causing irregular heartbeats. The issue with RF and cryoablation is that it can kill underlying tissues deeper than desired, which can cause serious safety issues by damaging the phrenic nerve or the esophagus. The advantage of pulsed field ablation is the energy is concentrated only into targeted tissues and it does not damage health, underlying tissue or neighboring anatomical structures.
The clinical studies to date have shown PFA is safer than thermal ablation; that alone makes it very appealing to the EP community. Clinical studies also have shown very good efficacy that is equal to, or better than, tradition thermal ablation techniques.
"I think over the next five years, we are really going to see pulsed field take up a lot of the thermal ablation space, especially for AF. And I think this being one of the first global, pivotal trial results, it certainly is baring out in that direction," explained Atul Verma, MD, of McGill University Health Center, in an interview with Cardiovascular Business at the American College of Cardiology (ACC) earlier this year. "The biggest advance here is the speed and safety. Over time, I think we are going to see even better outcomes in terms of efficacy."
Atrial fibrillation is the most common type of arrhythmia, and by 2050, up to 16 million Americans are projected to have AF . Given the prevalence of AF, researchers are continuously evaluating the latest approaches to deliver patient care safely and effectively. Today, the standard approaches to AF treatment have been medication, cardioversion and catheter ablation.
The findings of the following studies contribute to the growing body of evidence supporting PFA as a treatment option for patients with AF.
Study 1: Long-term Clinical Outcomes of Pulsed Field Ablation to Treat Patients with Paroxysmal Atrial Fibrillation
This study combines three of the first-in-human studies with a follow-up of 49±7 months to examine the success of PFA in preventing recurrent arrhythmias. The study found 73% of patients remain free from AFib/atrial flutter at the five-year mark. In a landmark analysis (excluding patients with AF recurrence <1 year), late on-set recurrence occurred in 11%. There were no delayed adverse effects seen PFA.
"Early in-human data suggests PFA offers improved safety and at least comparable, if not improved, efficacy in comparison to traditional thermal modalities," said Daniel Musikantow, MD, of the Icahn School of Medicine at Mount Sinai, in an HRS statement. "This analysis demonstrates no late-adverse effects and encouraging long-term outcomes, especially with the use of the optimized wave form."
Study 2: Influence of Atrial Arrhythmia Burden on Quality of Life in Patients Undergoing Pulsed Field Ablation
This was a sub-study of the PULSED AF trial that analyzed AF burden among patients following a PFA procedure using post-ablation monitoring methods similar to other reported trials . The authors collected 12,264 hours of Holter recordings in 300 patients. In the paroxysmal and persistent cohorts, AF burden was <10% in 87% and 82% of patients, respectively. Overall, 83% of paroxysmal atrial fibrillation (PAF) and 75% of persistent atrial fibrillation (PsAF) patients experienced ≤1 week of atrial arrhythmia recurrence on trans-telephonic monitoring .
"This sub-study of the PULSED AF trial set out to further validate the trial’s outcomes using additional post-ablation monitoring methods. These results show a predictable outcome following pulsed field ablation and were in line with other studies that used different monitoring methods," explained Verma in the same HRS statement. "As we look to evolve patient care, we are encouraged that this procedure may be able to improve quality of life for those undergoing ablation treatment for AF."
Study 3: European Real World Outcomes with Pulsed Field Ablation in Patients with Symptomatic Atrial Fibrillation
This late-breaker shared lessons from the multicenter EU-PORIA Registry to determine real-world safety, efficacy and the learning curve characteristics for the pentaspline, multielectrode PFA catheter across seven European, high-volume AF ablation centers. A total of 1,233 patients were treated by 42 operators with different AF ablation experience and different primary ablation modality backgrounds. The findings demonstrate a favorable single procedure success rate along with short procedure times in a real-world, all-comer AF patient population .
"These findings add to our understanding of how PFA will work as a treatment option for patients outside of controlled clinical studies and gave us new insight into how the new system is adopted and used by different operators across centers," Boris Schmidt, MD, with Cardioangiologisches Centrum Bethanien in Frankfurt, Germany, said in the HRS statement. "We look forward to future randomized multi-center trials to further compare PFA-guided ablation to thermal ablation modalities."