Pacemaker DDDNCT05015660
Conduction System Pacing With Left Bundle Branch Pacing as Compared to Standard Right Ventricular Pacing
A study testing Left bundle branch pacing lead and Right ventricular active fixation lead in people with Pacemaker DDD and Heart Block, run by McGill University Health Centre/Research Institute of the McGill University Health Centre at 1 site in Canada.
Trial summary
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). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Pacemaker DDD, Heart Block
- What is being tested?
- Left bundle branch pacing lead and Right ventricular active fixation lead
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 1,300 participants
- Where
- 1 siteCanada
- Study dates
- 1 Sep 2022to 1 Jan 2030
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age ≥ 18 years
- Patients with an ejection fraction of >35%
- Patients with an indication for ventricular pacing and high-degree atrioventricular block where the degree of anticipated RV pacing is >90% including:
- Third degree AV block
- Symptomatic or asymptomatic second-degree AV block
- First degree AV block ≥ 280ms with a narrow QRS, or ≥ 240ms with an intraventricular delay (QRS duration ≥120ms)
- Echocardiogram within the last 3 months, with ability to have DICOM images
Who cannot join
- Indication for an implantable cardioverter defibrillator
- Presence of a mechanical tricuspid valve
- Any prior attempt at implantation of an ICD, CRT, HBP, or LBBP
- Lack of capacity to consent
- Other serious medical condition with life expectancy of <2 years
- Pregnancy
- Patients in whom the conduction system abnormality is expected to be transient or recover over time
- Patients with permanent atrial fibrillation
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Canada1 site, 1 recruiting
- Recruiting
McGill University Health Centre-Research Institute
Montreal, Quebec, H3Y2T6
Fiorella Rafti, PhD, 514-934-1934, fiorella.rafti@mail.mcgill.ca
Jacqueline Joza, 514-934-1934 ext. 43158, jacqueline.joza@gmail.com
About this study
Official title: 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.
Read the 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.
- Conditions
- Pacemaker DDD, Heart Block
- Being tested
- Left bundle branch pacing lead, Right ventricular active fixation lead
- Keywords
- left bundle branch pacing
- Medical subject headings
- Heart Block
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Left bundle branch pacing leadDevice
Implantation of a left bundle branch pacing lead via sheath, to perform selective or non-selective pacing
Right ventricular active fixation leadDevice
Active fixation lead (standard)
| Study group | Role | What they receive |
|---|---|---|
| left bundle branch pacing | Experimental | Not described Receives: Device: Left bundle branch pacing lead |
| Right ventricular pacing | Active comparator | Not described Receives: Device: Right ventricular active fixation lead |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time to cardiovascular death
Clinical
Measured: 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%
Measured: 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
Measured: 24 months
Secondary outcomes (11)
Cardiovascular mortality
CV-related
Measured: 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.
Measured: 24 months
Total mortality
Total mortality
Measured: 24 months
Change in left ventricular ejection fraction
Echo parameter, change from baseline to 24 months
Measured: 24 months
Change in NTproBNP level
From baseline to 24 months
Measured: 24 months
Atrial fibrillation progression
Atrial fibrillation burden as noted on pacemaker
Measured: 24 months
Development of new tricuspid regurgitation
More than mild TR from baseline
Measured: 24 months
Presence of Mitral regurgitation
Progression/Development from baseline
Measured: 24 months
Change in Lead parameter
stability of impedance, sensing, thresholds
Measured: 24 months
Quality of Life Improvement
Health related quality of life score: Short Form 12
Measured: 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
Measured: 24 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Aug 2021
- Study start1 Sep 2022
- Primary completion1 Dec 2026 (estimated)
- Study completion1 Jan 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pacemaker DDDStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Prospective open-label randomized controlled trial (1:1) with blinded outcome adjudication
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 1,300 participants (estimated)
Sponsor and investigators
- Lead sponsor
- McGill University Health Centre/Research Institute of the McGill University Health Centre
- Sponsor type
- University, hospital or other
- Collaborators
- Heart and Stroke Foundation of Canada, Canadian Institutes of Health Research (CIHR)
- Responsible party
- Principal investigator, Jacqueline Joza, McGill University Health Centre/Research Institute of the McGill University Health Centre
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05015660
- Sponsor's protocol ID
- 2021-7452
- Status last verified
- Mar 2026
- First submitted
- 10 Aug 2021
- Last updated
- 11 Mar 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 11 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- LEFT Bundle Pacing vs Standard Right Ventricular Pacing for Heart Failure
- ClinicalTrials.gov ID
- NCT05015660
- Acronym / sponsor ID
- 2021-7452
- Conditions
- Pacemaker DDD, Heart Block
- Keywords
- left bundle branch pacing
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 1,300 participants (estimated)
- Lead sponsor
- McGill University Health Centre/Research Institute of the McGill University Health CentreUniversity, hospital or other
- Collaborators
- Heart and Stroke Foundation of Canada, Canadian Institutes of Health Research (CIHR)
- Study start
- 1 Sep 2022 (actual)
- Primary completion
- 1 Dec 2026 (estimated)
- Study completion
- 1 Jan 2030 (estimated)
- First posted
- 20 Aug 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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 design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
- Model description
- Prospective open-label randomized controlled trial (1:1) with blinded outcome adjudication
| Arm | Type | Receives |
|---|---|---|
| left bundle branch pacing | Experimental | Device: Left bundle branch pacing lead |
| Right ventricular pacing | Active comparator | Device: Right ventricular active fixation lead |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Age ≥ 18 years
- Patients with an ejection fraction of >35%
- Patients with an indication for ventricular pacing and high-degree atrioventricular block where the degree of anticipated RV pacing is >90% including:
- Echocardiogram within the last 3 months, with ability to have DICOM images
Key exclusion criteria (8 listed)
- Indication for an implantable cardioverter defibrillator
- Presence of a mechanical tricuspid valve
- Any prior attempt at implantation of an ICD, CRT, HBP, or LBBP
- Lack of capacity to consent
- Other serious medical condition with life expectancy of <2 years
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Left bundle branch pacing leadImplantation of a left bundle branch pacing lead via sheath, to perform selective or non-selective pacing | Device | left bundle branch pacing |
| Right ventricular active fixation leadActive fixation lead (standard) | Device | Right ventricular pacing |
Primary outcome
Time to cardiovascular death
Time frame: 36 months
Clinical
Time to first heart failure event
Time frame: 36 months
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%
Worsening LV end systolic volume index by 2 years
Time frame: 24 months
Defined as a 15% increase from baseline each year up to the two-year echo
11 secondary outcomes
Cardiovascular mortality
Time frame: 24 months
New visit for Heart Failure
Time frame: 24 months
Total mortality
Time frame: 24 months
Change in left ventricular ejection fraction
Time frame: 24 months
Change in NTproBNP level
Time frame: 24 months
Atrial fibrillation progression
Time frame: 24 months
Development of new tricuspid regurgitation
Time frame: 24 months
Presence of Mitral regurgitation
Time frame: 24 months
Change in Lead parameter
Time frame: 24 months
Quality of Life Improvement
Time frame: Evaluated at 1, 12, and 24 months, measure as compared to baseline
Safety of procedure and long-term safety
Time frame: 24 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 11 Mar 2026.
- Individual participant dataSharing planned: Undecided
Related trials for Pacemaker DDD
RecruitingObservational study
Prospective Database for Prediction of Atrial Fibrillation in Pacemaker and ICD Patients
Atrial Fibrillation, Pacemaker Ddd
RecruitingObservational study
Non-Invasive Method for Evaluation of Cardiac Resynchronization Therapy
Heart Failure, Pacemaker DDD
RecruitingObservational study
Left Bundle Branch Area Mapping for Conduction System Pacing
Left Bundle-Branch Block, Pacemaker DDD
Active, not recruitingPhase 4
The Leadless AV Versus DDD Pacing Study
Cardiac Pacemaker, Arrhythmias, Cardiac
Active, not recruiting
Danish Randomized Trial on Leadless vs Transvenous Pacing
AV Block
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Left bundle branch pacing lead and Right ventricular active fixation lead in people with Pacemaker DDD and Heart Block, run by McGill University Health Centre/Research Institute of the McGill University Health Centre at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 11 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Jacqueline Joza, MD MSc (514-934-1934 ext. 43158, jacqueline.joza@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time to cardiovascular death (time frame: 36 months). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Mar 2026.