Procedural Endpoint in Left Bundle Branch Area Pacing: Conduction System Capture Versus LV Septal Capture

NCT07804394 | Not Yet Recruiting DMC

• 1 other identifier: 4-2026-0630
• Study Type: interventional
• Target: 300
• Locations: 0 countries
• Sites: N/A

Brief Summary

This is a prospective, multicenter, randomized controlled trial designed to determine whether direct capture of the left ventricular conduction system must be achieved as the procedural endpoint of left bundle branch area pacing (LBBAP), or whether left ventricular septal capture alone is sufficient to obtain comparable clinical outcomes. A total of 300 patients aged 19 years or older who have a guideline-based indication for permanent pacemaker implantation for bradyarrhythmia, an expected ventricular pacing burden of 40% or more, and a planned LBBAP procedure will be enrolled at 5 or more centers in the Republic of Korea. Participants will be randomly assigned in a 1:1 ratio, stratified by baseline left ventricular ejection fraction (LVEF \<50% versus \>=50%), to one of two procedural strategies:

1. 1.LBBP mandatory group - the implanting operator continues the procedure, repositioning the lead as required, until left bundle branch pacing (LBBP) or left fascicular pacing (LFP) is confirmed by at least one predefined conduction system capture criterion.
2. 2.LVSP enough group - the operator may complete the procedure at his or her discretion once left ventricular septal pacing (LVSP) is confirmed, irrespective of whether direct conduction system capture is achieved.

Conditions

Bradycardia; Atrioventricular Block; Sick Sinus Syndrome; Cardiac Pacing; Artificial; Heart Conduction System; Bundle-Branch Block; Ventricular Dysfunction; Left; Cardiomyopathies

Keywords

LBBAP (left bundle branch area pacing); LBBP (left bundle branch pacing); LFP (left fascicular pacing); LVSP (left ventricular septal pacing); CSP (conduction system pacing); DSP (deep septal pacing); PICM (pacing-induced cardiomyopathy); LVEF; paced QRS duration; procedural endpoint; S-V6RWPT; V6-V1 interpeak interval

Outcome Measures

Primary Outcomes (1)

• Change from baseline in left ventricular ejection fraction (LVEF) at 12 months

  Absolute change in LVEF (percentage points) from baseline to 12 months, compared between the LBBP mandatory group and the LVSP enough group. LVEF is measured by the Simpson biplane method on transthoracic echocardiography and is determined by a central echocardiography core laboratory whose readers are blinded to treatment allocation, participating site, and acquisition time point. Baseline and 12-month studies are read as pairs by the same reader with the time point order randomly presented, in order to minimise measurement error in the change score. Only core laboratory values are used in the analysis; values reported by the enrolling site are collected for reference only. The primary analysis is an analysis of covariance with 12-month LVEF as the dependent variable and treatment group, baseline LVEF, and the stratification factor as covariates.

  Baseline and 12 months (±3 months) after implantation

Secondary Outcomes (15)

• Echocardiographic response rate at 12 months (proportion achieving LVESV reduction >=15%)

  Baseline and 12 months (±3 months)

• Incidence of pacing-induced cardiomyopathy (PICM), composite definition

  Baseline and 12 months (±3 months)

• Incidence of procedure-related major complications

  From procedure through 12 months

• Procedure time (min)

  Day of procedure (intraprocedural)

• Fluoroscopy time (min)

  Day of procedure (intraprocedural)

Study Arms (2)

LBBP mandatory group

EXPERIMENTAL

Participants undergo LBBAP in which direct capture of the left ventricular conduction system is mandatory. The procedure continues until left bundle branch pacing (LBBP) or left fascicular pacing (LFP) is confirmed by at least one predefined conduction system capture criterion. If conduction system capture cannot be obtained at the initial site, the lead is repositioned and the attempt repeated; more than three attempts are generally not recommended, with the final decision left to the operator. Failure to achieve conduction system capture is recorded as a protocol deviation.

Procedure: LBBAP with mandatory left ventricular conduction system capture (LBBP or LFP)

LVSP enough group

ACTIVE COMPARATOR

Participants undergo LBBAP in which left ventricular septal capture alone is accepted as the procedural endpoint. Once deep septal placement within the left ventricular subendocardial region is confirmed together with a terminal R-wave in lead V1 (LVSP), the operator may complete the procedure at his or her discretion irrespective of whether direct conduction system capture is achieved. Voluntary additional lead advancement in an attempt to obtain conduction system capture is permitted but not required.

Procedure: LBBAP with left ventricular septal capture as the accepted procedural endpoint (LVSP)

Interventions

LBBAP with mandatory left ventricular conduction system capture (LBBP or LFP) PROCEDURE

Left bundle branch area pacing is performed with an Ingevity Plus active-fixation helical pacing lead (Boston Scientific) and a commercially approved Boston Scientific pulse generator. The lead is advanced into the interventricular septum until direct capture of the left conduction system is confirmed by at least one of the following: a diagnostic QRS morphology transition during threshold testing or programmed stimulation (non-selective to selective LBBP, or LBBP to LVSP); S-V6RWPT \<75 ms with narrow QRS or simple right bundle branch block, or \<80 ms with advanced ventricular conduction disturbance; an LBB potential-to-V6RWPT interval equal to the stimulus-to-V6RWPT interval within 10 ms; or a V6-V1 interpeak interval \>44 ms. The lead is repositioned and the attempt repeated if capture is not obtained; more than three attempts are generally not recommended.

Also known as: LBBP mandatory strategy, Direct left ventricular conduction system capture strategy, Conduction system capture-guided LBBAP

LBBP mandatory group

LBBAP with left ventricular septal capture as the accepted procedural endpoint (LVSP) PROCEDURE

Left bundle branch area pacing is performed with the same Ingevity Plus active-fixation helical pacing lead (Boston Scientific) and commercially approved Boston Scientific pulse generator used in the comparator group. The procedure may be completed once left ventricular septal pacing is confirmed, defined as stable lead fixation in the deep interventricular septum reaching the left ventricular subendocardial region with a terminal R-wave present in lead V1, and without fulfilment of conduction system capture criteria. Deep septal position may be verified by the fluoroscopic fulcrum sign, contrast injection, echocardiography, or post-procedural computed tomography. Additional lead advancement to attempt conduction system capture is permitted at the operator's discretion but is not required by protocol.

Also known as: LVSP enough strategy, Left ventricular septal capture-only strategy, Anatomically guided LBBAP

LVSP enough group

Eligibility Criteria

• Age: 19 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients with a guideline-based indication for permanent pacemaker implantation for bradyarrhythmia and an expected ventricular pacing burden (VP) of 40% or more.
• Patients in whom a left bundle branch area pacing (LBBAP) procedure is planned in accordance with the above indication.
• Age 19 years or older.
• Provision of written informed consent to participate in the study.

You may not qualify if:

• Inability to understand the study or unwillingness to consent to participation.
• History of mechanical tricuspid valve replacement.
• History of myocardial infarction involving the interventricular septum.
• Life expectancy of 12 months or less.
• Inability to complete 12 months of follow-up for any reason.
• Pregnancy.
• History of cardiac transplantation.
• Indication for cardiac resynchronization therapy (CRT), defined as LVEF \<=35% and QRS duration \>=130 ms with left bundle branch block and NYHA functional class II to IV. This population is the subject of a separate randomized CRT trial and is distinct from the non-CRT pacemaker population studied here.
• Presence of an existing permanent pacemaker, implantable cardioverter-defibrillator, or CRT device (procedures performed for device replacement are not eligible).

Sponsors & Collaborators

• Yonsei University: lead

Related Publications (2)

• Jastrzebski M, Burri H, Kielbasa G, Curila K, Moskal P, Bednarek A, Rajzer M, Vijayaraman P. The V6-V1 interpeak interval: a novel criterion for the diagnosis of left bundle branch capture. Europace. 2022 Jan 4;24(1):40-47. doi: 10.1093/europace/euab164.

  PMID: 34255038 RESULT

• Abdelrahman M, Subzposh FA, Beer D, Durr B, Naperkowski A, Sun H, Oren JW, Dandamudi G, Vijayaraman P. Clinical Outcomes of His Bundle Pacing Compared to Right Ventricular Pacing. J Am Coll Cardiol. 2018 May 22;71(20):2319-2330. doi: 10.1016/j.jacc.2018.02.048. Epub 2018 Mar 10.

  PMID: 29535066 RESULT

MeSH Terms

Conditions

Bradycardia; Atrioventricular Block; Sick Sinus Syndrome; Arrhythmias, Cardiac; Bundle-Branch Block; Ventricular Dysfunction; Cardiomyopathies

Condition Hierarchy (Ancestors)

Heart Diseases; Cardiovascular Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Heart Block; Cardiac Conduction System Disease; Arrhythmia, Sinus

Central Study Contacts

Boyoung Joung, Professor

CONTACT

+82-2-2228-8460; cby6908@yuhs.ac

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: The implanting operator cannot be blinded because allocation determines the procedural endpoint. Outcome assessment is blinded: all echocardiographic studies are read by a central echocardiography core laboratory whose readers are blinded to treatment allocation, participating site, and acquisition time point, with baseline and 12-month studies read as pairs in randomly ordered time points. All electrocardiograms and intracardiac electrograms are independently re-adjudicated by a central ECG committee blinded to allocation. Both core laboratories operate independently of the investigators and the sponsor.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Two parallel groups with 1:1 allocation. All participants undergo an attempted LBBAP procedure; the groups differ only in the procedural endpoint that terminates the implantation. In the LBBP mandatory group the procedure continues until direct conduction system capture (LBBP or LFP) is confirmed by at least one predefined criterion. In the LVSP enough group the procedure may be completed once left ventricular septal capture is confirmed, irrespective of conduction system capture. The same lead and pulse generator platform is used in both groups.

Study Record Dates

• First Submitted: September 1, 2026
• First Posted: September 4, 2026
• Study Start: October 1, 2026
• Primary Completion (Estimated): October 1, 2029
• Study Completion (Estimated): November 30, 2029
• Last Updated: September 4, 2026

Record last verified: 2026-09