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

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: Not yet recruiting
• Conditions: Quality of Life; Atrial Fibrillation (Paroxysmal); Ablation Techniques
• Intervention / Treatment: Procedure: Tailored Strategy; Procedure: Control Strategy

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: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Tammy Knight; Phone Number: 613-696-7000; Email: TKnight@ottawaheart.ca

Study Locations

• Canada
  • Ontario
    • Ottawa, Ontario, Canada, K1Y 4W7
      • University of Ottawa Heart Institute
      • Sub-Investigator: David Birnie, MD
      • Contact: Tammy Knight; Phone Number: 613-696-7000; Email: tknight@ottawaheart.ca
      • Principal Investigator: F. Daniel Ramirez, MD

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
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

Outcome Measure	Measure Description	Time Frame
Freedom from recurrent atrial arrhythmia lasting >/= 30 seconds	Atrial arrhythmias include atrial fibrillation, atrial flutter, or atrial tachycardia.	Days 57 to 365 from repeat procedure.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Procedure duration	Time, in minutes, of the repeat procedure	From beginning of vascular access to removal of all catheters
Composite of major procedure-related complications	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	Visits and admissions related to recurrent atrial arrhythmias	Baseline to 12 months
Repeat Catheter Ablation procedure	Occurrence of additional ablation after the study index procedure.	Baseline to 12 months
Atrial Fibrillation Effect on Quality of Life	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

• Sponsor: Ottawa Heart Institute Research Corporation
• Investigators: Principal Investigator: F. Daniel Ramirez, MD, Ottawa Heart Institute Research Corporation

Study record dates

Study Major Dates

• Study Start (Estimated): December 1, 2026
• Primary Completion (Estimated): September 1, 2030
• Study Completion (Estimated): September 1, 2032

Study Registration Dates

• First Submitted: October 13, 2026
• First Submitted That Met QC Criteria: October 27, 2026
• First Posted (Actual): November 2, 2026

Study Record Updates

• Last Update Posted (Actual): November 3, 2026
• Last Update Submitted That Met QC Criteria: November 2, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Pathological Conditions, Signs and Symptoms; Atrial Fibrillation
• Other Study ID 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