Conduction System Pacing and AV Junction Ablation in Heart Failure With Atrial Fibrillation (SYNC AF-HTx)

December 30, 2025 updated by: Yonsei University

Safety and efficacY of conductioN System paCing and Atrioventricular Junctional Ablation Combined With ICD Implantation in Patients With End-stage Heart Failure and Atrial Fibrillation Eligible for Heart Transplantation (SYNC AF-HTx) : Multicenter Prospective Randomized Controlled Trial

The purpose of this study is to evaluate the safety and efficacy of conduction system pacing (CSP) using left bundle branch pacing (LBBP) and atrioventricular junction (AVJ) ablation in patients with end-stage heart failure and permanent atrial fibrillation (AF). Participants who are candidates for heart transplantation or left ventricular assist device (LVAD) implantation will be randomized to either the SYNC group (ICD implantation combined with LBBP and AVJ ablation) or the control group (ICD implantation only). The investigators will compare clinical outcomes, including mortality and heart failure hospitalization, between the two strategies over a 1-year follow-up period.

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

End-stage heart failure patients often face a poor prognosis due to comorbid permanent AF, which leads to irregular heart rates and worsens ventricular function. While implantable cardioverter-defibrillators (ICDs) are standard for preventing sudden cardiac death, they may not sufficiently prevent heart failure progression in patients with narrow QRS complexes. This study explores a "SYNC" strategy using LBBP and AVJ ablation to achieve ventricular synchronization and heart rate regularization. This is a multicenter, prospective, randomized (1:1), single-blind trial involving 120 participants.

Inclusion Criteria: Participants must have LVEF≤35%, permanent AF for >6 months, and be eligible for ICD implantation while awaiting heart transplantation or LVAD.

Intervention (SYNC Group): Participants receive an ICD with an LBBP lead (Medtronic SelectSecure™ 3830) and undergo AVJ ablation.

Control Group: Participants receive standard ICD implantation with a minimal ventricular pacing setting.

Follow-up: Clinical assessments, echocardiography, and device profiles will be monitored at baseline, 1, 3, 6, and 12 months post-procedure.

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.
120

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

  • South Korea
      • Seoul, South Korea
        • Division of Cardiology, Yonsei University College of Medicine.
        • Contact:

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

Candidates for ICD implantation (primary or secondary prevention). Permanent AF (>6 months) unsuitable for or failed catheter ablation. End-stage heart failure considering heart transplant or LVAD. LVEF ≤ 35 within 6 weeks before enrollment. NYHA functional class ≥ II. On GDMT for at least 3 months. Age ≥ 19 years.

Exclusion Criteria:

Existing LVAD or prior heart transplantation. Indications for cardiac resynchronization therapy (CRT). History of mechanical tricuspid valve replacement. Expected survival≤ 12 months. Inability to comply with the study protocol.

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: Single

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: SYNC group
Combined procedure of ICD implantation, LBBP lead insertion, and AVJ ablation.
Device: LBBP + AVJ Ablation with ICD
Insertion of an LBBP lead (Medtronic SelectSecure™ 3830) and performing AVJ ablation to ensure heart rate regularization and ventricular synchronization
Active Comparator: Control group
Standard ICD implantation with minimal ventricular pacing strategy.
Device: ICD Only
Participants receive standard ICD implantation with a minimal ventricular pacing strategy

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
Composite of all-cause mortality, heart failure hospitalization, or urgent heart transplantation
Time Frame: Time Frame: Up to 12 months
Occurrence of the first event among the composite components
Time Frame: Up to 12 months

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
All cause mortality
Time Frame: Up to 12 months
All cause deaths including cardiovascular and non-cardiovascular deaths.
Up to 12 months
Cardiovascular mortality
Time Frame: Up to 12 months
Cardiovascular death
Up to 12 months
Heart failure hospitalization
Time Frame: Up to 12 months
An unplanned outpatient or emergency department visit or inpatient hospitalization in which the patient presented with signs and symptoms consistent with heart failure and required intravenous therapy.
Up to 12 months
Urgent heart transplantation
Time Frame: Up to 12 months
Urgent heart transplantation
Up to 12 months
LV systolic function
Time Frame: 6months and 12months
LVEF measure by echocardiography
6months and 12months

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.
Yonsei University

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.
January 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.
January 1, 2028

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.
May 1, 2028

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).
December 18, 2025

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.
December 30, 2025

First Posted (Estimated)

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.
January 12, 2026

Study Record Updates

Last Update Posted (Estimated)

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.
January 12, 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.
December 30, 2025

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.
December 1, 2025

More Information

Terms related to this study

Keywords

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.
  • 4-2025-1357

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

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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