Diaphragmatic Evaluation by Fluoroscopy to Identify Phrenic Nerve Dysfunction Related to Electroporation (DEFINE-PFA)

Diaphragmatic Evaluation by Fluoroscopy to Identify Phrenic Nerve Dysfunction Related to Electroporation Prospective Multicentre Study on the Evaluation of the Incidence of Diaphragmatic Paralysis After Pulsed Field Ablation Procedures to Treat Atrial Fibrillation

Pulsed Field Ablation (PFA) represents a recent advance in the treatment of atrial fibrillation (AF), with a safety profile potentially superior to traditional thermal techniques, such as radiofrequency or cryoablation. Its mechanism of action allows tissue selectivity which in theory limits damage to extracardiac structures. However, several cases of right diaphragmatic paralysis have been reported in the literature after PFA, particularly during applications on the right pulmonary veins, near the right phrenic nerve. The available data are from studies without specific diaphragmatic monitoring. The diagnosis of diaphragmatic paralysis is most often based on chest X-ray, a static examination of limited sensitivity, especially for the detection of incomplete paralysis. To date, no prospective multicentre study has evaluated the incidence of diaphragmatic paralysis after PFA with systematic dynamic imaging, such as fluoroscopy, considered the gold standard for the diagnosis of unilateral paralysis.

Study Overview

• Status: Not yet recruiting
• Conditions: Atrial Fibrillation
• Intervention / Treatment: Procedure: Dynamic fluoroscopy

Detailed Description

The current study, DEFINE-PFA, aims to include 250 patients spread over 9 centres (France, New-Zealand and Canada). Each patient will benefit from dynamic fluoroscopy before and after the procedure. A new fluoroscopy will be performed at 3 months in patients with a significant reduction (>15%) in postoperative diaphragmatic amplitude.

The primary endpoint is based on the appearance of post-procedure inter-hemi diaphragmatic asymmetry, rather than a simple decrease in craniocaudal amplitude compared to the reference fluoroscopy. Indeed, the absolute diaphragmatic amplitude is highly dependent on the examination conditions, in particular the degree of cooperation of the patient and the intensity of forced inspiration, making inter-examination comparisons unreliable. Conversely, the simultaneous comparison of the two hemidiaphragms during the same inspiratory cycle makes it possible to attenuate these biases by using the contralateral hemidiaphragm as a stable internal reference. Pre-procedure fluoroscopy is nevertheless systematically performed in order to check the absence of basic asymmetry.

The threshold of 15% inter-hemi diaphragmatic asymmetry was empirically retained, in the absence of a cut-off validated in the literature for dynamic fluoroscopy. In diaphragmatic ultrasound, asymmetry is generally considered significant for differences in amplitude > 20% between the two hemi domes, but these measurements are performed successively, which makes them sensitive to variations between respiratory cycles. Conversely, fluoroscopy allows simultaneous observation of the two hemidiaphragms during the same respiratory cycle, offering a more reliable comparison. This threshold aims to detect significant asymmetry while minimizing false positives related to physiological variability.

• Study Type: Interventional
• Enrollment (Estimated): 250
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Tessa BERGOT, MSc; Phone Number: +33144907033; Email: tessa.bergot@sfcardio.fr

Study Locations

• Canada
  • Montreal, Canada, QC H1T 1C8
    • Montreal Heart Institute
    • Contact: Laurent MACLE, MD
• France
  • Chambray-lès-Tours, France, 37170
    • CHRU de Tours - Hôpital Trousseau
    • Contact: Arnaud BISSON, MD
  • Lyon, France, 69004
    • CHU de Lyon - Hôpital Croix-Rousse
    • Contact: Sami FAREH, MD
  • Pau, France, 64046
    • Centre Hospitalier de Pau - Hôpital François Mitterrand
    • Contact: Hugues Bader, MD
  • Pessac, France, 33604
    • Chu de Bordeaux - Hopital Haut-Leveque
    • Contact: Romain TIXIER, MD
  • Saint-Denis, France, 93200
    • Centre Cardiologique du Nord
    • Contact: William ESCANDE, MD
  • Strasbourg, France, 67000
    • Institut Cardiovasculaire de Strasbourg - Clinique Rhéna
    • Contact: Babé BAKOUBOULA, MD
  • Toulouse, France, 31300
    • Clinique Pasteur
    • Contact: Serge Boveda, MD
• New Zealand
  • Auckland, New Zealand, 1023
    • Auckland City Hospital
    • Contact: Nigel LEVER, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Men and women aged 18 years or older at the time of signing the consent (age≥ 18).
• Diagnosis of paroxysmal or persistent atrial fibrillation, documented in any type of means: ECG, Holter, invasive monitoring (memories of an implantable device) or not (connected objects).
• Indication for ablation decided as part of routine care, according to the recommendations of learned societies.
• First, ablation procedure (including pulmonary vein isolation) planned with the use of a commercially available Pulsed Field Ablation catheter.
• Possibility of performing a fluoroscopic diaphragmatic evaluation before and after the operation (before discharge from the hospital).
• Free, informed and signed consent by the patient before any data collection

Exclusion Criteria:

• Known history of diaphragmatic paralysis (right or bilateral) or pre-existing clinical suspicion.
• History of atrial fibrillation ablation.
• History of neuromuscular disease.
• History of major thoracic surgery or chronic pulmonary pathology that may impair diaphragmatic kinetics.

• Evidence of diaphragmatic paralysis on the pre-procedure fluoroscopy loop, defined as:

  • Cranio-caudal excursion amplitude ≤35 mm on both hemidiaphragms, Or
  • An asymmetry in contraction amplitude ≥15% between the two sides.
• Inability to perform a post-procedure follow-up fluoroscopy (logistical limitation, patient refusal, contraindication to irradiation).
• Pregnancy or breastfeeding in progress.
• Concurrent participation in another interventional study that may interfere with the objectives of this research.
• Major impairment in cognitive function or inability to understand the objectives of the study or sign a valid consent.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention; Systematic observation of an additional examination (dynamic fluoroscopy) performed before and after a Pulsed Field Ablation procedure, as part of the standard management of atrial fibrillation.	Procedure: Dynamic fluoroscopy; Fluoroscopic loop recording or continuous digital scopy of the thoracic window, over at least one complete breathing cycle at maximum amplitude.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diaphragmatic paralysis	Post-procedural occurrence of diaphragmatic contraction asymmetry, defined as a ≥15% reduction in the cranio-caudal amplitude of a hemi-diaphragm, relative to the contralateral side, measured by dynamic fluoroscopy during a forced breathing cycle, and absent on pre-procedure fluoroscopy.	Day1: Before the Pulsed Field Ablation and after the Pulsed Field Ablation (at hospital discharge between 2 and 30 hours after ablation, according to a rigorously standardized protocol in all participating centres)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate of complete or partial recovery of diaphragmatic function at 3 months.	For patient with diaphragmatic paralysis observed at inclusion visit, diaphragmatic contraction asymmetry evaluation will be redo after 3 months.	At 3 months
Evaluation of symptoms associated with diaphragmatic paralysis	Presence / absence of symptoms : dyspnea, discomfort on inspiration, decreased physical capacity, sleep disturbances.	Day 1, at 3 months
Evaluation of the efficiency of the procedure	Comparison, between patients who experienced diaphragmatic paralysis after ablation and those who did not, of the duration of the procedure (in minutes), the duration of the endoscopy (in minutes), the total number of applications and the type of catheter used.	Day1

Collaborators and Investigators

• Sponsor: French Cardiology Society
• Collaborators: Circle Safe; IHU Lyric; ADIMEP
• Investigators: Study Chair: Romain TIXIER, MD, University Hospital, Bordeaux; Study Director: Frédéric FRANCESCHI, MD, CHU Marseille

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): May 31, 2027
• Study Completion (Estimated): May 31, 2027

Study Registration Dates

• First Submitted: March 2, 2026
• First Submitted That Met QC Criteria: March 6, 2026
• First Posted (Actual): March 10, 2026

Study Record Updates

• Last Update Posted (Actual): March 10, 2026
• Last Update Submitted That Met QC Criteria: March 6, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Fluoroscopy; Pulsed Field Ablation; Diaphragmatic monitoring
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Pathological Conditions, Signs and Symptoms; Atrial Fibrillation
• Other Study ID Numbers: 2025-07

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