Catheter Ablation of Advanced Forms of Atrial Fibrillation (ENDO MAZE)

The purpose of this study is to evaluate feasibility, safety, and efficacy of pulmonary vein isolation combined with posterior left atrial isolation and multiple linear lesions in both atria in patients with persistent and long-standing persistent atrial fibrillation.

Study Overview

• Status: Enrolling by invitation
• Conditions: Persistent Atrial Fibrillation; Persistent Atrial Fibrillation Longstanding
• Intervention / Treatment: Device: Endovascular ablation set mimicking cox maze 4 procedure.

Detailed Description

Patients with long-standing and persistent atrial fibrillation with severely dilated left atrium will undergo pulmonary vein isolation, box-lesion set of posterior wall, lateral mitral line (Marshall vein ablation and coronary sinus ablation per operator's discretion, anterior line, cavotricuspid line, superior caval vein isolation, intercaval line and inferior septal line. Ablations will be performed with either radiofrequency energy or pulsed field ablation at operator's discretion. Block at each line will be checked at the end of the procedure. The procedure will be performed with compliance of producer recommendation and hospital protocol.

All patients will be invited back at three months after index procedure for an invasive remap. At the remap procedure, pulmonary veins and posterior wall will be checked for isolation and all the additional lines will be checked for conduction block. Any gaps in lines will be ablated per operator's discretion.

Patients will undergo a period follow-up visit at 3, 6, and 12-month period. They will undergo a medical history taking, physical examination, ECG, and 7-day Holter ECG. Any documented atrial arrhythmia lasting more than 30 seconds after 8 week blanking period will be documented as a recurrence of atrial fibrillation.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Slovenia
  • Osrednjaslovenska
    • Ljubljana, Osrednjaslovenska, Slovenia, 1000
      • University Medical Centre Ljubljana

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• persistent atrial fibrillation or long-standing persistent atrial fibrillation
• severely enlarged left atrium (LAVI above 50 ml/m2)

Exclusion Criteria:

• contraindications for electroporation
• contraindications for general anaesthesia
• age above 80 years
• less than 1 year life expectancy
• thrombus formation in left atrium
• acute life-threatening disease
• severe valvular disease requiring intervention
• previous ablation in left atrium
• secondary atrial fibrillation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• 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: Cohort; Long-standing and persistent atrial fibrillation undergoing catheter ablation mimicking cox-maze procedure	Device: Endovascular ablation set mimicking cox maze 4 procedure.; Endovascular pulmonary vein isolation, posterior left atrial isolation and multiple linear lesions in both atria using electroporation and radiofrequency energy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Atrial arrhythmia recurrence	Atrial fibrillation/atrial tachycardia/atrial undulation lasting more than 30s after 8 week blanking period and without antiarrhythmic drug therapy. Assessed with 7-day Holter ECG at 3, 6, 12 months after index procedure.	12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Efficacy of endovascular Cox maze procedure	Atrial fibrillation burden will be assessed with 7-day Holter ECG at 3, 6 and 12 months post procedure.	12 month
Interventions	Initiations of antiarrhythmic drug therapy, number of cardioversions, number of repeat procedures after index procedure will be assessed.	12 months
Durability of ablation lines and isolations	Number of durable blocks across ablation lines and durable isolations (pulmonary veins, superior vena cava) on invasive remap at 3 months will be assessed.	3 months
Safety of catheter ablation procedure	Incidence of adverse events defined as events, which require prolonged hospitalization, additional intervention or permanent damage to patients health or cause death in a 180 day period after catheter ablation.	6 months

Collaborators and Investigators

• Sponsor: University Medical Centre Ljubljana
• Investigators: Principal Investigator: Tine Prolic Kalinsek, MD, UMCL

Study record dates

Study Major Dates

• Study Start (Actual): March 25, 2026
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 1, 2028

Study Registration Dates

• First Submitted: February 19, 2026
• First Submitted That Met QC Criteria: February 25, 2026
• First Posted (Actual): March 3, 2026

Study Record Updates

• Last Update Posted (Actual): April 6, 2026
• Last Update Submitted That Met QC Criteria: March 31, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: atrial fibrillation; pulsed field ablation; cox maze
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Pathological Conditions, Signs and Symptoms; Atrial Fibrillation
• Other Study ID Numbers: 145780304

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: the data will be shared upon reasonable request.
• IPD Sharing Time Frame: 01-MAR-2026 until 01-MAR-2030
• IPD Sharing Access Criteria: Researchers upon reasonable request.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes