A Prospective Observational Study Evaluating the Incidence of Silent Cerebral Lesions and Procedural Safety Following Atrial Fibrillation Ablation Using the VARIPULSE™ Pulsed Field Ablation System (VARIACE)

January 15, 2026 updated by: Eue-Keun Choi, Seoul National University Hospital

Study Type: Observational Study

Goal:

The goal of this study is to evaluate the incidence and burden of silent cerebral lesions (SCLs) detected on brain magnetic resonance imaging (MRI) after pulsed field ablation (PFA) for atrial fibrillation (AF). PFA is a new non-thermal ablation technique that selectively targets cardiac tissue while minimizing damage to surrounding structures. The study focuses on adult patients with paroxysmal or persistent AF who undergo left-atrial ablation using the VARIPULSE PFA system.

Study Overview

Status

Recruiting

Conditions

Detailed Description

Main Questions the Study Aims to Answer:

What percentage of patients develop silent cerebral lesions after PFA using the VARIPULSE system?

What are the lesion characteristics (number, size, and location) and total lesion burden on MRI?

Are there any early neurological or cognitive changes related to these MRI findings?

Comparison:

This is an observational, single-arm study with no active control group. However, the findings will be compared with historical data from previous studies of thermal ablation (radiofrequency and cryoballoon) to explore potential differences in neurological safety.

Participant Activities:

Participants in this study will:

Undergo brain MRI (DWI and FLAIR sequences) within 1-3 days after PFA to detect any silent cerebral lesions.

Complete neurological and cognitive assessments (for example, tests of memory, language, and attention) to identify subtle functional changes.

Receive routine clinical follow-up for AF management according to institutional standard of care.

Background:

Silent cerebral lesions are small ischemic brain injuries seen on MRI that cause no immediate symptoms but have been linked to later cognitive decline and increased risk of clinical stroke. They are known to occur in 10-40 % of patients after conventional AF ablation using radiofrequency or cryoballoon energy. Because PFA employs electrical pulses rather than heat, its effects on cerebral safety may differ. The VARIPULSE system integrates a variable-loop, multipolar PFA catheter with a three-dimensional electro-anatomical mapping system to improve procedural precision and reduce risk.

Significance:

As PFA use expands in clinical practice, understanding its neurological safety is crucial. This study will provide quantitative MRI data and standardized neurological evaluations to define the cerebral safety profile of PFA. The results are expected to inform procedural optimization and help establish evidence-based strategies for safer AF ablation.

Study Type

Observational

Enrollment (Estimated)

40

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • South Korea
    • Jongro-ku
      • Seoul, Jongro-ku, South Korea, 03080
        • Recruiting
        • Seoul National Universtiy Hospital, Seoul
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

This study is designed as a registry to evaluate safety without a control group.

The target sample size was determined with reference to previous studies that assessed the incidence of silent cerebral lesions (SCLs) using post-procedural MRI, in which approximately 30 to 40 patients were typically included.

Description

Inclusion Criteria:

1) Patients undergoing atrial fibrillation ablation using the Varipulse™ catheter

Exclusion Criteria:

  1. Individuals under 19 years of age
  2. Patients who undergo concomitant radiofrequency ablation of the left atrium during the procedure
  3. Patients with a history of stroke or transient ischemic attack (TIA)
  4. Patients who have previously undergone ablation or surgery for atrial fibrillation
  5. Patients with intracardiac thrombus or embolic events within the past 90 days
  6. Patients who have experienced cardiac surgery or acute coronary syndrome within the past 90 days
  7. Patients with contraindications to oral anticoagulant therapy, or those who require temporary discontinuation of anticoagulation due to procedural complications (e.g., cardiac tamponade)
  8. Patients with a left ventricular ejection fraction (LVEF) of less than 35%
  9. Women who are currently pregnant or planning to become pregnant during the study period
  10. Patients with a life expectancy of less than one year
  11. Patients at increased risk during MRI scanning (e.g., those with pacemakers or other metallic implants affected by MRI, or those with severe claustrophobia)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of silent cerebral lesions (SCLs)
Time Frame: From enrollment to the end of treatment at 3 months

The proportion of patients in whom silent cerebral lesions (SCLs) are detected on brain MRI performed within 72 hours after atrial fibrillation ablation using the VARIPULSE PFA catheter.

Definition of SCL:

A lesion that shows positive findings on both diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences.
From enrollment to the end of treatment at 3 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number and total volume (mm³) of silent cerebral lesions (SCLs) in patients with positive SCL findings after the procedure.
Time Frame: From enrollment to the end of treatment at 3 months
Number and total volume (mm³) of silent cerebral lesions (SCLs) in patients with positive SCL findings after the procedure.
From enrollment to the end of treatment at 3 months
Neurological complications
Time Frame: From enrollment to the end of treatment at 3 months
Incidence of newly developed neurological symptoms or signs (e.g., motor weakness, speech impairment, cognitive changes) after the procedure.
From enrollment to the end of treatment at 3 months
Cognitive function
Time Frame: From enrollment to the end of treatment at 3 months

Change in Montreal Cognitive Assessment (MoCA) score from baseline (pre-procedure) to 3 months after the procedure.

Cognitive function was evaluated using the Montreal Cognitive Assessment (MoCA; range: 0-30; higher scores indicate better cognitive performance). A score of 26 or higher is generally considered to represent normal cognitive function.
From enrollment to the end of treatment at 3 months
Quality of Life (QoL)
Time Frame: From enrollment to the end of treatment at 3 months
Patient-reported quality of life was assessed using the Atrial Fibrillation Effect on QualiTy of Life (AFEQT) questionnaire. The AFEQT overall summary score ranges from 0 to 100, where a score of 0 represents the most severe symptoms and functional limitation, and a score of 100 indicates the best possible quality of life (higher scores indicate better clinical outcomes).
From enrollment to the end of treatment at 3 months
General health status
Time Frame: From enrollment to the end of treatment at 3 months
General health status was measured using the EuroQol 5-Dimension (EQ-5D) index. The index scores typically range from less than 0 (representing a state 'worse than death') to 1 (representing 'full health'), where higher scores indicate a better overall health state.
From enrollment to the end of treatment at 3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Seoul National University Hospital

Collaborators

Biosense Webster, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

December 26, 2025

Primary Completion (Estimated)

December 31, 2027

Study Completion (Estimated)

December 31, 2027

Study Registration Dates

First Submitted

December 29, 2025

First Submitted That Met QC Criteria

January 15, 2026

First Posted (Actual)

January 23, 2026

Study Record Updates

Last Update Posted (Actual)

January 23, 2026

Last Update Submitted That Met QC Criteria

January 15, 2026

Last Verified

October 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • VARIACE study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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