Cerebral Microembolization During Pulmonary Vein Isolation: Comparison of Different Pulsed Field Ablation Systems (MICROPFA)

Cerebral Microembolization During Pulmonary Vein Isolation: a Randomized Comparison of Different Pulsed Field Ablation Systems

This prospective, randomized, parallel-group interventional study will compare cerebral microembolization during pulmonary vein isolation between different pulsed field ablation systems in patients with paroxysmal or persistent atrial fibrillation. Adult patients with an indication for catheter ablation will be randomized to one of the included ablation systems: PulseSelect, Varipulse, Farapulse, Sphere-9, or Sphere-360. Microembolic signals will be assessed using transcranial Doppler before and after the procedure. The primary outcome will be the difference in the change in microembolic signal burden, expressed as ΔMES, between the different ablation systems.

Study Overview

• Status: Not yet recruiting
• Conditions: Ablation of Arrhythmia's
• Intervention / Treatment: Device: Pulsed field ablation using PulseSelect system; Device: Pulsed field ablation using Varipulse system; Device: Pulsed field ablation using Farapulse system; Device: Pulsed field ablation using Sphere-9 system; Device: Pulsed field ablation using Sphere-360 system

Detailed Description

This study is designed as a prospective, randomized, parallel-group interventional trial conducted at Clinical Hospital Dubrava, Zagreb, Croatia and University Hospital Center Sisters of Charity, Zagreb, Croatia. The study will include adult patients with paroxysmal or persistent atrial fibrillation who have a clinical indication for catheter ablation with pulmonary vein isolation.

Eligible patients will be randomized using a computer-generated randomization sequence to undergo pulmonary vein isolation with one of the following pulsed field ablation systems: PulseSelect, Varipulse, Farapulse, Sphere-9, or Sphere-360. All procedures will be performed according to standard clinical practice, with continuous periprocedural anticoagulation in accordance with current guidelines.

Cerebral microembolization will be assessed using transcranial Doppler. The examination will be performed immediately before the ablation procedure and repeated after the procedure. The presence and number of microembolic signals will be recorded. This will allow assessment of changes in microembolic signal burden within each group and comparison of these changes between different pulsed field ablation systems.

Demographic, clinical, and procedural data will be collected, including age, sex, type of atrial fibrillation, comorbidities, procedure duration, number of ablation applications, and procedural complications. The study will also record procedure-related clinical neurological events.

The primary outcome will be the difference in the change in the number of microembolic signals before and after the procedure, expressed as ΔMES, between the different pulsed field ablation systems. Secondary outcomes will include within-group changes in microembolic signal burden, incidence of new microembolic signals after the procedure, association between procedural parameters and ΔMES, and occurrence of procedure-related neurological events.

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ivan Zeljković, PhD,MD; Phone Number: +385917823289; Email: ivanzeljkov@gmail.com
• Study Contact Backup: Name: Mihovil Santini, MD; Phone Number: +385958101778; Email: 023miho@gmail.com

Study Locations

• Croatia
  • Zagreb, Croatia, 10000
    • UH Dubrava
    • Principal Investigator: Ivan Zeljković, MD, Phd
    • Sub-Investigator: Mihovil Santini, MD
  • Zagreb, Croatia, 10000
    • University Hospital Center Sisters of Charity, Zagreb, Croatia

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Age 18 years or older
• Paroxysmal or persistent atrial fibrillation
• Indication for catheter ablation with pulmonary vein isolation
• Feasibility of transcranial Doppler assessment
• Signed informed consent

Exclusion Criteria:

• Recent stroke or transient ischemic attack
• Significant cerebrovascular disease preventing reliable transcranial Doppler assessment
• Severe valvular or structural heart disease
• Pregnancy or breastfeeding
• Inability to receive anticoagulation

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

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: PulseSelect PFA; Participants randomized to this arm will undergo clinically indicated pulmonary vein isolation using the PulseSelect pulsed field ablation system. Cerebral microembolic signals will be assessed by transcranial Doppler before and after the procedure.	Device: Pulsed field ablation using PulseSelect system; Pulmonary vein isolation will be performed using the PulseSelect pulsed field ablation system in patients with paroxysmal or persistent atrial fibrillation undergoing clinically indicated catheter ablation. Cerebral microembolic signals will be assessed by transcranial Doppler before and after the procedure.
Active Comparator: Varipulse PFA; Participants randomized to this arm will undergo clinically indicated pulmonary vein isolation using the Varipulse pulsed field ablation system. Cerebral microembolic signals will be assessed by transcranial Doppler before and after the procedure.	Device: Pulsed field ablation using Varipulse system; Pulmonary vein isolation will be performed using the Varipulse pulsed field ablation system in patients with paroxysmal or persistent atrial fibrillation undergoing clinically indicated catheter ablation. Cerebral microembolic signals will be assessed by transcranial Doppler before and after the procedure.
Active Comparator: Farapulse PFA; Participants randomized to this arm will undergo clinically indicated pulmonary vein isolation using the Farapulse pulsed field ablation system. Cerebral microembolic signals will be assessed by transcranial Doppler before and after the procedure.	Device: Pulsed field ablation using Farapulse system; Pulmonary vein isolation will be performed using the Farapulse pulsed field ablation system in patients with paroxysmal or persistent atrial fibrillation undergoing clinically indicated catheter ablation. Cerebral microembolic signals will be assessed by transcranial Doppler before and after the procedu
Active Comparator: Sphere-9 PFA; Participants randomized to this arm will undergo clinically indicated pulmonary vein isolation using the Sphere-9 pulsed field ablation system. Cerebral microembolic signals will be assessed by transcranial Doppler before and after the procedure.	Device: Pulsed field ablation using Sphere-9 system; Pulmonary vein isolation will be performed using the Sphere-9 pulsed field ablation system in patients with paroxysmal or persistent atrial fibrillation undergoing clinically indicated catheter ablation. Cerebral microembolic signals will be assessed by transcranial Doppler before and after the procedure.
Active Comparator: Sphere-360 PFA; Participants randomized to this arm will undergo clinically indicated pulmonary vein isolation using the Sphere-360 pulsed field ablation system. Cerebral microembolic signals will be assessed by transcranial Doppler before and after the procedure	Device: Pulsed field ablation using Sphere-360 system; Pulmonary vein isolation will be performed using the Sphere-360 pulsed field ablation system in patients with paroxysmal or persistent atrial fibrillation undergoing clinically indicated catheter ablation. Cerebral microembolic signals will be assessed by transcranial Doppler before and after the procedure

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in microembolic signal burden after pulmonary vein isolation	Difference in the number of cerebral microembolic signals detected by transcranial Doppler before and after pulmonary vein isolation, expressed as ΔMES, compared between the different pulsed field ablation systems.	During procedure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Within-group change in microembolic signal burden	Change in the number of cerebral microembolic signals detected by transcranial Doppler before and after pulmonary vein isolation within each pulsed field ablation system group.	During procedure
Incidence of new microembolic signals after ablation	Proportion of participants with newly detected cerebral microembolic signals on transcranial Doppler after pulmonary vein isolation.	Immediately after the ablation procedure
Procedure-related clinical neurological events	Occurrence of clinically evident neurological events related to the ablation procedure, including stroke or transient ischemic attack.	From the start of the ablation procedure through 72 hours after the procedure
Association between procedure duration and ΔMES	Association between total procedure duration and the change in cerebral microembolic signal burden before and after pulmonary vein isolation.	During procedure
Association between number of ablation applications and ΔMES	Association between the number of pulsed field ablation applications delivered during pulmonary vein isolation and the change in cerebral microembolic signal burden before and after the procedure.	During procedure

Collaborators and Investigators

• Sponsor: Ivan Zeljkovic
• Collaborators: University Hospital Dubrava; University Hospital Center Sisters of Charity, Zagreb, Croatia

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): January 20, 2027

Study Registration Dates

• First Submitted: May 14, 2026
• First Submitted That Met QC Criteria: May 21, 2026
• First Posted (Actual): May 27, 2026

Study Record Updates

• Last Update Posted (Actual): May 27, 2026
• Last Update Submitted That Met QC Criteria: May 21, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Atrial fibrillation; Pulmonary vein isolation; Pulsed field ablation; Cerebral microembolization
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Pathological Conditions, Signs and Symptoms; Atrial Fibrillation
• Other Study ID Numbers: 2026/0423-11

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