Conduction System Pacing With Left Bundle Branch Pacing as Compared to Standard Right Ventricular Pacing

LEFT Bundle Pacing vs Standard Right Ventricular Pacing for Heart Failure

High burden right ventricular (RV) pacing has been shown to increase cardiovascular mortality, incidence of heart failure (HF), worsen left ventricular (LV) function and accelerate the development of atrial fibrillation (AF). High percentage ventricular pacing and wider paced QRS in the setting of normal baseline LV ejection fractions have consistently been shown to be independent risk factors for pacing-induced cardiomyopathy. Left bundle branch pacing (LBBP) has emerged as a potential alternative pacing mechanism that may avoid LV dyssynchrony and pacing-induced LV dysfunction by mimicking native electrical conduction.

Study Overview

• Status: Recruiting
• Conditions: Heart Block; Pacemaker DDD
• Intervention / Treatment: Device: Right ventricular active fixation lead; Device: Left bundle branch pacing lead

Detailed Description

We hypothesize that in patients with high degree AV block with anticipated ventricular pacing >90%, and an EF >35% patients undergoing LBBP will demonstrate a significantly lower number of the primary composite endpoint of cardiovascular death, heart failure events, and change in LVESVi as compared to standard RV pacing. Echos will be performed at baseline, 12, 24, and 36 months. NTproBNPs are performed at baseline and follow-up. There will be a core echo lab, and blinded adjudication of ECGs and events.

• Study Type: Interventional
• Enrollment (Estimated): 1300
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jacqueline Joza, MD MSc; Phone Number: 43158 514-934-1934; Email: jacqueline.joza@gmail.com
• Study Contact Backup: Name: Fiorella Rafti, PhD; Phone Number: 514-934-1934; Email: fiorella.rafti@mail.mcgill.ca

Study Locations

• Canada
  • Quebec
    • Montreal, Quebec, Canada, H3Y2T6
      • Recruiting
      • McGill University Health Centre-Research Institute
      • Contact: Fiorella Rafti, PhD; Phone Number: 514-934-1934; Email: fiorella.rafti@mail.mcgill.ca
      • Contact: Jacqueline Joza; Phone Number: 43158 514-934-1934; Email: jacqueline.joza@gmail.com
      • Principal Investigator: Jacqueline Joza
      • Principal Investigator: Atul Verma

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age ≥ 18 years
2. Patients with an ejection fraction of >35%

3. Patients with an indication for ventricular pacing and high-degree atrioventricular block where the degree of anticipated RV pacing is >90% including:

   1. Third degree AV block
   2. Symptomatic or asymptomatic second-degree AV block
   3. First degree AV block ≥ 280ms with a narrow QRS, or ≥ 240ms with an intraventricular delay (QRS duration ≥120ms)
4. Echocardiogram within the last 3 months, with ability to have DICOM images

Exclusion Criteria:

1. Indication for an implantable cardioverter defibrillator
2. Presence of a mechanical tricuspid valve
3. Any prior attempt at implantation of an ICD, CRT, HBP, or LBBP
4. Lack of capacity to consent
5. Other serious medical condition with life expectancy of <2 years
6. Pregnancy
7. Patients in whom the conduction system abnormality is expected to be transient or recover over time
8. Patients with permanent atrial fibrillation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Right ventricular pacing	Device: Right ventricular active fixation lead; Active fixation lead (standard)
Experimental: left bundle branch pacing	Device: Left bundle branch pacing lead; Implantation of a left bundle branch pacing lead via sheath, to perform selective or non-selective pacing

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to cardiovascular death	Clinical	36 months
Time to first heart failure event	Defined as: (i) Emergency department (ED) visits or hospitalization for HF (requiring signs and symptoms consistent with congestive heart failure (CHF) that is responsive to oral or parenteral medications); (ii) intensification of therapy (intravenous diuretic therapy on an outpatient basis); or (iii) indication for device upgrade to CRT due to deteriorating LV function defined as an absolute decline in LVEF ≥ 10% from baseline and an LVEF ≤ 40%	36 months
Worsening LV end systolic volume index by 2 years	Defined as a 15% increase from baseline each year up to the two-year echo	24 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cardiovascular mortality	CV-related	24 months
New visit for Heart Failure	Heart failure visit is defined as: i) Emergency department visit or hospitalization for signs and symptoms of HF that is responsive to oral or intravenous diuretics ii) intensification of therapy defined as outpatient intravenous diuretic therapy, and iii) device upgrade to cardiac resynchronization therapy.	24 months
Total mortality	Total mortality	24 months
Change in left ventricular ejection fraction	Echo parameter, change from baseline to 24 months	24 months
Change in NTproBNP level	From baseline to 24 months	24 months
Atrial fibrillation progression	Atrial fibrillation burden as noted on pacemaker	24 months
Development of new tricuspid regurgitation	More than mild TR from baseline	24 months
Presence of Mitral regurgitation	Progression/Development from baseline	24 months
Change in Lead parameter	stability of impedance, sensing, thresholds	24 months
Quality of Life Improvement	Health related quality of life score: Short Form 12	Evaluated at 1, 12, and 24 months, measure as compared to baseline
Safety of procedure and long-term safety	Procedural and long-term safety of left bundle pacing	24 months

Collaborators and Investigators

• Sponsor: McGill University Health Centre/Research Institute of the McGill University Health Centre
• Collaborators: Canadian Institutes of Health Research (CIHR); Heart and Stroke Foundation of Canada

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2022
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): January 1, 2030

Study Registration Dates

• First Submitted: August 10, 2021
• First Submitted That Met QC Criteria: August 16, 2021
• First Posted (Actual): August 20, 2021

Study Record Updates

• Last Update Posted (Actual): March 11, 2026
• Last Update Submitted That Met QC Criteria: March 9, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: left bundle branch pacing
• Additional Relevant MeSH Terms: Cardiac Conduction System Disease; Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Pathological Conditions, Signs and Symptoms; Heart Block
• Other Study ID Numbers: 2021-7452

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