Pulsed Field Ablation Versus Sham Procedure in Atrial Fibrillation: Insights from the PFA-SHAM Randomized Clinical Trial

Highlight

• Pulsed field ablation (PFA) significantly reduces atrial fibrillation (AF) recurrence compared with a sham procedure.
• PFA markedly improves patients’ quality of life as measured by the Atrial Fibrillation Effect on Quality-of-Life (AFEQT) scores.
• PFA lowers AF burden and decreases psychological distress symptoms assessed by the Hospital Anxiety and Depression Scale (HADS).
• This is the first major blinded, sham-controlled trial addressing placebo effects in catheter ablation for AF.

Study Background

Atrial fibrillation is a prevalent and burdensome cardiac arrhythmia associated with increased risks of stroke, heart failure, and diminished quality of life. Catheter ablation is a widely applied therapeutic procedure aiming to electrically isolate arrhythmogenic foci, especially within the pulmonary veins, to reduce AF episodes and improve symptoms. Over the past decades, conventional radiofrequency or cryoballoon ablation methods have shown efficacy in reducing AF recurrence. However, most prior ablation trials were unblinded, raising concerns about placebo effects influencing subjective outcomes such as symptom relief, anxiety, and quality of life metrics. Pulsed field ablation, a novel ablation modality using nonthermal, tissue-selective electroporation, has shown early promise with improved safety profiles. Yet, robust randomized controlled trials with blinded assessments including sham controls were lacking to definitively establish its efficacy beyond placebo effects.

Study Design

The PFA-SHAM randomized clinical trial was a prospective, single-blind, sham-controlled study with blinded endpoint adjudication. It enrolled 60 patients with highly symptomatic AF, defined by an AFEQT score less than 50, indicating poor quality of life due to AF symptoms. Patients were randomly assigned in a 1:1 ratio to undergo pulsed field ablation or a sham procedure mimicking ablation without energy delivery. Implantable cardiac monitors were implanted in all participants to ensure continuous, objective rhythm monitoring throughout the 6-month follow-up. The study established two co-primary endpoints assessed at 6 months: (1) time to first recurrence of atrial tachyarrhythmia and (2) change from baseline in AFEQT scores comparing PFA and sham groups. Secondary endpoints included AF burden quantified as proportion of time in arrhythmia and psychological distress using the Hospital Anxiety and Depression Scale (HADS).

Key Findings

The PFA group demonstrated striking superiority over sham across primary and secondary outcomes. Only 2 out of 30 patients (6.7%) in the PFA arm experienced AF recurrence by 6 months, compared to 25 of 30 patients (83.3%) in the sham arm. This corresponded to a posterior hazard ratio of 19.6 (95% Bayesian credible interval, 6.7-76.9) favoring PFA, with probability of superiority exceeding 99%.

Regarding quality of life, AFEQT scores improved by a mean of 43.9±18.1 points in the PFA group versus 11.3±27.9 points in the sham group, confirming a substantial and clinically meaningful benefit (median difference 32.6 points; 95% Bayesian credible interval 20.2-44.9).

AF burden was almost eliminated in the PFA group (median 0 [IQR 0-0]) compared to persistent burden in the sham group (median 0.43 [IQR 0.04-3.47]), with a significant median difference of −0.39 (95% credible interval −2.5 to −0.1).

Psychological distress assessed by HADS showed a greater reduction in the PFA-treated patients, with a median change of −4 points compared to −0.5 points with sham (median difference −3.5; 95% credible interval −6.0 to −1.0).

No significant safety concerns were reported. The blinded design and continuous rhythm monitoring provide high confidence in the validity of these findings.

Expert Commentary

This trial represents a milestone in electrophysiology research by rigorously evaluating ablation with a sham control, thereby eliminating bias from placebo and patient expectation. It conclusively establishes pulsed field ablation as an effective, well-tolerated intervention that not only reduces the objective burden of AF but also markedly enhances patients’ subjective well-being and mental health. The electroporation mechanism used by PFA selectively targets myocardial tissue with minimal collateral damage, which could explain the favorable safety and efficacy profiles.

Limitations include the relatively small sample size and short follow-up duration; longer-term outcomes are needed to confirm sustained benefits. The single-blind design, although practical, does allow possibility of subtle unblinding. Also, generalizability should be assessed in real-world diverse populations. Nevertheless, these data are highly supportive of PFA’s incorporation as a frontline ablation approach.

Conclusion

The PFA-SHAM randomized clinical trial provides compelling evidence that pulsed field ablation significantly reduces AF recurrence and burden, improves quality of life, and alleviates psychological distress versus sham in patients with symptomatic atrial fibrillation. This study addresses critical gaps regarding placebo effects in electrophysiology trials and supports pulsed field ablation as a transformative advancement in AF management. Future research should explore long-term outcomes, cost-effectiveness, and optimization of patient selection to consolidate the role of PFA in routine clinical practice.

Funding and ClinicalTrials.gov

The trial was registered at ClinicalTrials.gov under identifier NCT05717725. Details regarding funding sources were not specified in the primary report.

References

1. Osmancik P, Neuzil P, Hozmanova J, Petru J, Herman D, Kralovec S, et al. Pulsed Field Ablation Versus Sham to Treat Atrial Fibrillation: The PFA-SHAM Randomized Clinical Trial. Circulation. 2026 May 26;153(25):1984-1998. PMID: 42186803.

2. Kirchhof P, Benussi S, Kotecha D, et al. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association of Cardio-Thoracic Surgery (EACTS). Eur Heart J. 2020 Aug 21;42(5):373-498.

3. Reddy VY, Anic A, Koruth J, et al. Pulsed Field Ablation for Atrial Fibrillation: Early Clinical Experience. JACC Clin Electrophysiol. 2020;6(11):1495-1508.