Paroxysmal Atrial Fibrillation Repeat Ablation Strategies With Durably Isolated Pulmonary Veins (PARADISO)

November 2, 2026 updated by: Ottawa Heart Institute Research Corporation

Paroxysmal Atrial Fibrillation Repeat Ablation Strategies With Durably Isolated Pulmonary Veins (PARADISO): a Vanguard Study

This study looks at participants who have undergone an ablation procedure for atrial fibrillation previously, and atrial fibrillation has occurred and a second ablation procedure is needed. The study will randomize participants to either a tailored strategy for ablation or to widening the pulmonary vein isolation procedure with or without cavotricuspid isthmus ablation. The goal is to improve freedom from recurrent atrial arrhythmias at 12 months.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

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

This is a study of patients who have undergone an ablation procedure for AF but in whom AF recurred and who are undergoing a second ablation procedure. Specifically, the investigators are interested in the group of patients whose PVs are still "isolated" during that second procedure because doctors are unsure of how best to ablate them. It is even possible that doing any more ablation in those patients is harmful.

The study will compare (1) an ablation strategy that includes commonly done ablation steps that tackle abnormalities found during the procedure (i.e., ablating "low voltage areas", searching for and ablating other arrhythmias called supraventricular tachycardias, and in some patients ablating the "posterior wall") to (2) an ablation strategy that reinforces or extends the PVI step only. In both groups, cavotricuspid isthmus ablation is also performed, if not already successfully done previously. The vanguard study will follow participants for 1 year, with a 3 year follow up planned if feasibility is met. Participants will be required to wear a Holter monitor at various timepoints and will be asked to complete atrial fibrillation and quality of life questionnaires.

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 (Estimated)

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.
60

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

  • Canada
    • Ontario
      • Ottawa, Ontario, Canada, K1Y 4W7
        • University of Ottawa Heart Institute
        • Sub-Investigator:
          • David Birnie, MD
        • Contact:
        • Principal Investigator:
          • F. Daniel Ramirez, MD

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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Paroxysmal atrial fibrillation with durable pulmonary vein isolation (PVI)
  • Age >/= 18 years
  • at least one episode of atrial fibrillation documented on 12-lead ECG, Holter monitor, or loop recorder in the preceding 12 months
  • ability to provide informed consent

Exclusion Criteria:

  • Persistent atrial fibrillation
  • documented sustained atrial tachycardia or atypical atrial flutter.
  • Previous atrial ablation excluding PVI or cavotricuspid Isthmus (CTI) ablation (having undergoing more than one procedure is acceptable as long as only PVI +/- CTI ablation was preformed)
  • previous left atrial surgery
  • known PV stenosis or history of PV intervention
  • active intracardiac thrombus
  • contraindication to systemic anticoagulation
  • hypertrophic cardiomyopathy
  • significant left-sided valve disease (moderate or severe mitral or aortic stenosis or regurgitation)
  • significant congenital heart disease, including atrial septal defects or PV abnormalities (patent foramen ovale is not an exclusion)
  • active pregnancy
  • participation or anticipated participation in another clinical trial that could affect the results of this trial
  • unwillingness or inability to adhere fully with study procedures and follow up

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: Randomized
  • Interventional Model: Parallel 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.
Experimental: Tailored Strategy

Homogenizing left atrium/atrial (LA) low voltage areas (LVAs), ablating inducible supraventricular tachycardia (SVTs), and if no abnormality is identified, performing empiric posterior wall isolation (PWI )followed by cavotricuspid isthmus (CTI) ablation (if successful CTI ablation not performed previously).
Procedure: Tailored Strategy

Homogenizing left atrium/atrial (LA) low voltage areas (LVAs), ablating inducible supraventricular tachycardia (SVTs), and if no abnormality is identified, performing empiric posterior wall isolation (PWI )followed by cavotricuspid isthmus (CTI) ablation (if successful CTI ablation not performed previously).
Other: Control Strategy

Widening wide area circumferential ablation (WACA) lines and cavotricuspid isthmus (CTI) ablation if not successfully performed previously.
Procedure: Control Strategy

Widening wide area circumferential ablation (WACA) lines and cavotricuspid isthmus (CTI) ablation if not successfully performed previously.

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
Freedom from recurrent atrial arrhythmia lasting >/= 30 seconds
Time Frame: Days 57 to 365 from repeat procedure.

Atrial arrhythmias include atrial fibrillation, atrial flutter, or atrial tachycardia.
Days 57 to 365 from repeat procedure.

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
Procedure duration
Time Frame: From beginning of vascular access to removal of all catheters

Time, in minutes, of the repeat procedure
From beginning of vascular access to removal of all catheters
Composite of major procedure-related complications
Time Frame: Baseline to 12 months

Procedure-related complications include embolic events, pulmonary vein stenosis, cardiac perforation, major bleeding, atrioesophageal fistula, or death)
Baseline to 12 months
Emergency Room visits or re-hospitalizations
Time Frame: Baseline to 12 months

Visits and admissions related to recurrent atrial arrhythmias
Baseline to 12 months
Repeat Catheter Ablation procedure
Time Frame: Baseline to 12 months

Occurrence of additional ablation after the study index procedure.
Baseline to 12 months
Atrial Fibrillation Effect on Quality of Life
Time Frame: Baseline to 12 months.

Measured by the Atrial Fibrillation Effect on Quality of Life questionnaire. Scale of 0-100, with 100 being best quality of life.
Baseline to 12 months.

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.
Ottawa Heart Institute Research 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: F. Daniel Ramirez, MD, Ottawa Heart Institute Research Corporation

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 (Estimated)

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.
December 1, 2026

Primary Completion (Estimated)

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.
September 1, 2030

Study Completion (Estimated)

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.
September 1, 2032

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).
October 13, 2026

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.
October 27, 2026

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.
November 2, 2026

Study Record Updates

Last Update Posted (Actual)

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.
November 3, 2026

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 2, 2026

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.
May 1, 2026

More Information

Terms related to this study

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.
  • 20260577-01H

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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