Effect of a Bigger Cryoballoon on the Total Antral Lesion Size: Evaluation of POLARx FIT (BETTER-FIT)

November 15, 2025 updated by: Sing-Chien Yap, MD, PhD, Erasmus Medical Center
The investigators will prospectively evaluate the extent of antral lesion created by the 31 mm balloon size of a novel cryoballoon catheter (POLARx FIT). In 20 patients with paroxysmal atrial fibrillation, the investigators will perform pre- and post-ablation high-definition 3D maps to quantify the extent of lesion created by the 31 mm POLARx FIT cryoballoon.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Rationale: The next generation POLARx cryoablation balloon (CB) catheter will have the option of to deliver cryotherapy with the current balloon size of 28 mm or a new, larger 31 mm size by changing the inner balloon pressure (POLARx FIT, Boston Scientific). Currently, there is no data on the extension of left atrial (LA) lesion formation with the 31 mm balloon size of the POLARx FIT cryoablation balloon catheter. The hypothesis is that a larger CB size results in a wide antral circumferential lesion.

Objective: The primary objective is to evaluate the antral lesion size using ultrahigh-density (UHDx) mapping pre- and post-cryoablation with the 31 mm balloon size CB. Secondary objectives are the proportion of pulmonary veins (PVs) where a 31 mm CB could be positioned to achieve a grade 4 occlusion and the single shot success rate with the 31 mm balloon size CB.

Study design: Single-center, single-arm, prospective study with pre- and post-PVI UHDx mapping.

Study population: Twenty adult patients with paroxysmal AF who are scheduled to undergo pulmonary vein isolation (PVI) with a CB.

Intervention: Patients will undergo pre- and post-ablation UHDx mapping (Orion catheter and Rhythmia 3D-mapping system, Boston Scientific) during the index procedure.

Main study parameters/endpoints: The primary endpoint is the extent of the antral lesion size. Secondary endpoints are the proportion of PVs with grade 4 occlusion with the 31 mm balloon size CB, the single shot success rate of the 31 mm balloon size CB, difference in rate of achieving grade 4 occlusion in comparison to the standard (28 mm) size.

Nature and extent of the burden and risks associated with participation, benefit, and group relatedness: A UHDx mapping will be acquired before and after complete PVI. The procedures will be performed under deep sedation, which is standard practice for CB procedures in our institution. The risk of additional mapping is limited. LA mapping is a standard diagnostic method for patients undergoing PVI with radiofrequency ("standard-of-care"). In the current study, UHDx mapping will now be used in patients undergoing PVI with CB. The most important complication of additional intracardiac mapping is cardiac tamponade, but this risk is low (<0.5%).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
20

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Netherlands
    • South Holland
      • Rotterdam, South Holland, Netherlands, 3015 GD
        • Erasmus Medical Center

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. History of symptomatic paroxysmal AF
  2. Subjects who are indicated for a PVI according to the 2020 ESC guidelines for the diagnosis and management of AF
  3. Subjects who are willing and capable of providing informed consent
  4. Subjects who are willing and capable of participating in all testing associated with this clinical investigation
  5. Subjects whose age is 18 years or above

Exclusion Criteria:

  1. Any known contraindication to an AF ablation or anticoagulation
  2. History of previous left atrial ablation or surgical treatment of AF, atrial flutter, or atrial tachycardia
  3. AF secondary to electrolyte imbalance, thyroid disease, or any other reversible or non-cardiac cause

  4. Significant structural heart disease as evidenced by:

    1. Left ventricular ejection fraction <45% based on most recent transthoracic echocardiogram (TTE) performed <6 months prior to enrollment
    2. LA diameter >55 mm based on most recent TTE performed <6 months prior to enrollment
    3. Previous cardiac surgery
    4. Previous cardiac valvular surgical or percutaneous procedure
    5. Interatrial baffle, closure device, patch, or occluder
    6. Unstable angina or ongoing myocardial ischemia
    7. Moderate or severe valvular heart disease on most recent TTE performed <6 months prior to enrolment
    8. Congenital heart disease
    9. Left atrial thrombus
  5. History of blood clotting or bleeding disease
  6. Stroke or transient ischemic attack <3 months prior to enrollment
  7. Active systemic infection
  8. Common ostium PV >24 mm defined by CT-scan
  9. Pregnant, lactating, or women of childbearing potential who are, or plan to become, pregnant during the time of the study
  10. Subjects who are currently enrolled in another investigational study or registry that would directly interfere with the current study

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

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Other: Study population
This study will have only a single arm. Patients will undergo pulmonary vein isolation using the 31 mm balloon size of POLARx FIT. High-definition 3D maps will be constructed before and after cryoablation to assess the antral lesion size.
Device: POLARx FIT cryoballoon
Patients will undergo cryoablation with the 31 mm balloon size of the POLARx FIT cryoballoon.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Percentage of Ablated Left Atrial Posterior Wall With a 31 mm Balloon Size POLARx FIT
Time Frame: Interprocedural (directly after cryoablation)
Low-voltage areas will be quantified using a bipolar voltage <0.3 mV. The sum of the posterior ablated areas of all pulmonary veins is expressed as a percentage of the total left atrial posterior wall.
Interprocedural (directly after cryoablation)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Percentage of Pulmonary Veins With Grade 4 Occlusion With a 31 mm Balloon Size POLARx FIT
Time Frame: Interprocedural (before cryoablation)
A grade 4 occlusion is defined as complete contrast stasis. Cine acquisitions of contrast vein occlusions was analyzed by two experienced observers.
Interprocedural (before cryoablation)
Percentage of Pulmonary Veins With a Single Shot Success Rate Using a 31 mm Balloon Size POLARx FIT Cryoablation Catheter
Time Frame: Interprocedural (directly after cryoablation)
Pulmonary vein isolation will be determined using conventional criteria: entry- and exit-block as assessed with the circular mapping catheter (POLARMAP).
Interprocedural (directly after cryoablation)

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Erasmus Medical Center

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Boston Scientific Corporation

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Sing-Chien Yap, MD, PhD, Erasmus Medical Center

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 2, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 29, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 23, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 21, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 30, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 31, 2023

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 4, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 15, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • MEC-2023-0325
  • NL84423.078.23 (Registry Identifier: CCMO)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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