Heart Failure - NYHA II - IVRESYNC-PACENCT07684547
REstoration of SYNChronous Cardiac Function Due to Physiologic cArdiac Pacing Modalities With Clinical Endpoints
An observational study of Heart Failure - NYHA II - IV and Left Bundle Branch Area Pacing, run by University of Pecs at 1 site in Hungary.
Trial summary
The goal of this observational study is to evaluate the long-term clinical outcomes of physiologic cardiac resynchronization therapy (CRT) using conduction system pacing strategies compared with conventional biventricular CRT in patients with heart failure with reduced ejection fraction (HFrEF) and electrical… Read more about this study
- Who is it for?
- Ages 18 to 100 years
- Conditions the study is for
- Heart Failure - NYHA II - IV, Left Bundle Branch Area Pacing, Left Bundle Branch Block
- What is being tested?
- Physiologic cardiac resynchronization using conduction system pacing and selective LV lead optimization.
- Type of treatment
- Medical device
- How many people
- 50 participants
- Where
- 1 siteHungary
- Study dates
- 29 Jun 2026to 29 Jun 2031
- How long will I take part?
- 24 Months
- Phase
- Observational
- 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 to 100 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population consists of adult patients with heart failure with reduced ejection fraction (HFrEF) who are treated at the University of Pécs Clinical Centre Heart Institute and meet contemporary guideline indications for cardiac resynchronization therapy (CRT). Eligible participants have symptomatic heart failure despite guideline-directed medical therapy, left ventricular systolic dysfunction, and evidence of electrical dyssynchrony manifested by left bundle branch block (LBBB) or intraventricular conduction delay (IVCD). The prospective cohort includes patients undergoing conduction system pacing-based CRT as part of routine clinical care, while the historical control cohort includes patients previously treated with conventional biventricular CRT at the same institution. The study population represents a real-world heart failure population routinely referred for CRT implantation in tertiary cardiovascular care.
Who may be able to join
- Age ≥18 years.
- Symptomatic heart failure despite guideline-directed medical therapy.
- Left ventricular ejection fraction (LVEF) ≤40%.
- Indication for cardiac resynchronization therapy according to contemporary ESC guideline recommendations.
- QRS duration ≥150 ms with either:
- Left bundle branch block (LBBB), or Intraventricular conduction delay (IVCD).
Show all 9Show fewer
- Planned implantation of a CRT system
- Ability to provide written informed consent
- Expected survival greater than 24 months.
Who cannot join
- Age <18 years and Age 100 < years
- Pregnancy or breastfeeding.
- Inability or unwillingness to provide informed consent.
- Life expectancy <12 months due to non-cardiac comorbidities.
- Active systemic infection or infection involving a cardiac implantable electronic device.
- Reversible causes of heart failure expected to improve without CRT.
Show all 10Show fewer
- Participation in another interventional clinical trial that may affect study outcomes.
- Inability to comply with follow-up requirements.
- Missing essential baseline or follow-up data (retrospective cohort).
- Any condition that, in the opinion of the investigators, would make participation inappropriate or interfere with study assessments.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
About this study
Official title: REstoration of SYNChronous Cardiac Function Due to Physiologic cArdiac Pacing Modalities With Clinical Endpoints RESYNC-PACE
The goal of this observational study is to evaluate the long-term clinical outcomes of physiologic cardiac resynchronization therapy (CRT) using conduction system pacing strategies compared with conventional biventricular CRT in patients with heart failure with reduced ejection fraction (HFrEF) and electrical dyssynchrony.
The main questions it aims to answer are:
Read more
- Does physiologic CRT (including left bundle branch area pacing [LBBAP] and LBBAP-optimized CRT) reduce the combined risk of all-cause mortality and heart failure hospitalization compared with conventional biventricular CRT?
- Does physiologic CRT improve cardiac function and reverse ventricular remodeling more effectively than conventional CRT?
Participants receiving physiologic CRT as part of routine clinical care will undergo standard follow-up evaluations, including electrocardiography, echocardiography, laboratory testing, and device interrogation. Clinical outcomes will be collected prospectively for 24 months and compared with a historical cohort of patients treated with conventional biventricular CRT.
The study will assess clinical outcomes, echocardiographic response, electrical resynchronization parameters, and device-related safety in a real-world heart failure population.
Read the detailed description
Background
Heart failure with reduced ejection fraction (HFrEF) is associated with substantial morbidity, mortality, and healthcare utilization despite continuous advances in guideline-directed medical therapy. Cardiac resynchronization therapy (CRT) has become an established treatment for patients with symptomatic HFrEF and electrical dyssynchrony. Conventional biventricular pacing improves ventricular synchrony and clinical outcomes; however, approximately one-third of treated patients do not achieve a satisfactory response.
Conduction system pacing (CSP), particularly left bundle branch area pacing (LBBAP), has emerged as a physiological pacing strategy capable of directly engaging the native His-Purkinje conduction system. Compared with conventional biventricular pacing, CSP may produce more physiological ventricular activation, narrower paced QRS complexes, improved electrical synchrony, and greater reverse ventricular remodeling. Nevertheless, evidence regarding its long-term effectiveness in routine clinical practice remains limited, particularly in heterogeneous populations with different conduction abnormalities.
Study Rationale
The RESYNC-PACE study was designed to evaluate the effectiveness of individualized physiologic cardiac resynchronization strategies in a real-world population of patients with HFrEF requiring CRT.
The study investigates two complementary physiologic CRT approaches according to the underlying conduction disturbance. In patients with typical left bundle branch block (LBBB), left ventricular lead implantation is guided by the qLV ratio to achieve optimal electrical resynchronization through individualized coronary sinus lead positioning. In patients with intraventricular conduction delay (IVCD), a conduction system pacing strategy is applied using left bundle branch area pacing. When conduction system pacing alone results in incomplete electrical correction, defined by a paced QRS duration greater than 130 ms, an additional coronary sinus left ventricular lead is implanted to establish Left Bundle Branch Area Pacing Optimized Cardiac Resynchronization Therapy (LOT-CRT).
This individualized treatment algorithm reflects contemporary physiological concepts of ventricular resynchronization rather than a single implantation strategy and represents the principal scientific concept investigated in the study.
Scientific Objectives
The study aims to determine whether physiologic CRT strategies provide superior long-term clinical outcomes compared with conventional biventricular CRT when implemented in routine clinical practice.
In addition to evaluating clinical outcomes, the study investigates the relationship between electrical resynchronization, ventricular reverse remodeling, myocardial scar characteristics assessed by cardiac magnetic resonance imaging, and long-term prognosis. Particular emphasis is placed on identifying imaging-, electrocardiographic-, and device-derived predictors of CRT response that may facilitate patient selection and optimization of resynchronization therapy.
Study Methodology
RESYNC-PACE is a single-center, ambispective observational cohort study performed at the University of Pécs Clinical Centre Heart Institute. Consecutive patients undergoing physiologic CRT constitute the prospective cohort, while a historical cohort of patients treated with conventional biventricular CRT serves as the comparator.
All therapeutic procedures are performed as part of routine clinical care using commercially available CE-marked cardiac implantable electronic devices according to their approved indications and current international guideline recommendations. The study does not introduce experimental devices or procedures beyond standard clinical practice but prospectively evaluates the clinical performance of an individualized physiological CRT algorithm.
The comprehensive study database integrates demographic, clinical, electrocardiographic, echocardiographic, cardiac magnetic resonance imaging, procedural, device-derived, and long-term follow-up data. This integrated approach enables detailed evaluation of the mechanisms underlying CRT response and supports the development of patient-specific resynchronization strategies.
Expected Clinical Significance
The RESYNC-PACE study is expected to generate real-world evidence regarding the effectiveness of conduction system pacing-guided CRT strategies and individualized resynchronization algorithms. The findings may improve patient selection, optimize implantation strategies for different conduction disorders, and contribute to the growing evidence supporting physiologic cardiac resynchronization therapy in patients with heart failure.
- Conditions
- Heart Failure - NYHA II - IV, Left Bundle Branch Area Pacing, Left Bundle Branch Block, Intraventricular Conduction Delay, Resynchronization Therapy
- Being tested
- Physiologic cardiac resynchronization using conduction system pacing and selective LV lead optimization.
- Keywords
- carrdiac resynchornization therapy, Physiologic Pacing, Conduction System Pacing, Electrical Resynchronization, Physiologic CRT
- Medical subject headings
- Bundle-Branch Block
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Physiologic cardiac resynchronization using conduction system pacing and selective LV lead optimization.Device
Also called Cardiac resynchronization therapy using left bundle branch area pacing with or without LV lead optimization., Cardiac resynchronization guided by conduction system pacing to improve ventricular synchrony.
Conduction System Pacing-Guided Cardiac Resynchronization Therapy is an individualized resynchronization strategy used in patients with heart failure, reduced left ventricular ejection fraction, and electrical dyssynchrony. The intervention is based on direct recruitment of the native cardiac conduction system through left bundle branch area pacing (LBBAP). During implantation, electrical resynchronization is assessed using electrocardiographic and device-derived parameters. In patients with intraventricular conduction delay or incomplete electrical correction, additional left ventricular pacing may be provided using a coronary sinus lead, resulting in Left Bundle Branch Area Pacing Optimized Cardiac Resynchronization Therapy (LOT-CRT). The intervention aims to achieve more physiological ventricular activation than conventional biventricular pacing, improve electrical synchrony, promote reverse ventricular remodeling, and reduce heart failure-related adverse events.
| Study group | Role | What they receive |
|---|---|---|
| Left bundle branch block patients | LBBB Cohort (qLV-guided Cardiac Resynchronization Therapy)
Patients in this cohort have symptomatic heart failure with reduced left ventricular ejection fraction and complete left bundle branch block (LBBB) according to contemporary guideline criteria. Cardiac resynchronization therapy is performed using a personalized implantation strategy guided by the qLV ratio, defined as the interval between QRS onset and local left ventricular activation divided by the intrinsic QRS duration. The left ventricular lead is positioned at the site with the longest achievable electrical delay to maximize resynchronization benefit. Patients receive either conventional biventricular CRT or LOT- CRT according to clinical decision-making and anatomical feasibility. The cohort is followed longitudinally to evaluate the relationship between qLV-guided lead placement, electrical resynchronization, reverse ventricular remodeling, heart failure hospitalization, and all-cause mortality. Receives: Device: Physiologic cardiac resynchronization using conduction system pacing and selective LV lead optimization. | |
| Intraventricular conduction delay patients | IVCD Cohort (Conduction System Pacing-Guided Resynchronization Strategy)
Patients in this cohort have symptomatic heart failure with reduced left ventricular ejection fraction and intraventricular conduction delay (IVCD) without typical left bundle branch block morphology. The resynchronization strategy is guided by the degree of electrical correction achieved with conduction system pacing. During implantation, left bundle branch area pacing (LBBAP) is attempted and paced QRS duration is assessed. If conduction system pacing alone results in a paced QRS duration greater than 130 ms, a Left Bundle Branch Area Pacing Optimized Cardiac Resynchronization Therapy (LOT-CRT) system is implanted by adding a left ventricular lead to further improve ventricular synchrony. The cohort is followed longitudinally to evaluate the association between electrical resynchronization, reverse ventricular remodeling, heart failure hospitalization, and all-cause mortality. Receives: Device: Physiologic cardiac resynchronization using conduction system pacing and selective LV lead optimization. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Composite of All-Cause Mortality and Heart Failure Hospitalization
Time to first occurrence of the composite endpoint of all-cause mortality or hospitalization due to worsening heart failure during the 24-month follow-up period.
Measured: 24 months
Secondary outcomes (4)
Change in Left Ventricular Ejection Fraction (LVEF)
Change in left ventricular ejection fraction measured by transthoracic echocardiography between baseline and 24-month follow-up.
Ejection fraction is measured in percentage (%). Improvement in ejection fraction is detected as increase in percentage-value.
Measured: Baseline to 24 months
Change in Left Ventricular End-Systolic Volume ( LV ESV)
Change in left ventricular end-systolic volumen measured by echocardiography between baseline and 24-month follow-up.
Left ventricular end-systolic volume in measured in mililiters ( ml) , decrease in LV ESV is a sign of clinical response on therapy.
Measured: Baseline to 24 months
Change in paced QRS Duration
Reduction in QRS duration following cardiac resynchronization therapy compared with baseline electrocardiographic measurements.
Paced QRS duration is measured in miliseconds (ms). Decrease in paced QRS duration compared to preoperative QRS duration is marked as a good signal in cardiac resynchronization therapy.
Measured: Baseline to 24 months
New York Heart Association Heart Failure Functional Status
Change in New York Heart Association (NYHA) functional class from baseline to follow-up. Stage I-IV.
NYHA improvement is detected as decrease in NYHA stage grade.
Measured: Baseline to 24 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Jul 2026
- Study start29 Jun 2026 (estimated)
- Primary completion29 Jun 2030 (estimated)
- Study completion29 Jun 2031 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Heart Failure - NYHA II - IVStudies 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 50 participants (estimated)
- Target duration
- 24 Months
Sponsor and investigators
- Lead sponsor
- University of Pecs
- Sponsor type
- University, hospital or other
- Collaborators
- Medical University of Pecs
- Responsible party
- Principal investigator, Peter Ezer, University of Pecs
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07684547
- Sponsor's protocol ID
- FF107 RESYNC-PACE ver1.0
- Other IDs
- Biotronik Research Grant FF107
- Acronym
- RESYNC-PACE
- Status last verified
- Jul 2026
- First submitted
- 28 Jun 2026
- Last updated
- 10 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Undecided: ndividual participant data will be shared only in a de-identified form and in accordance with applicable data protection regulations, institutional policies, and informed consent provisions. Data sharing may be limited where participant privacy, ethical considerations, or legal requirements prevent full disclosure of individual-level data.
Publications
Guo J, Luo W, Zhao S, Cui H, Wang X, Li X. Conduction system pacing compared with biventricular pacing for cardiac resynchronization therapy: a systematic review and meta-analysis. Front Cardiovasc Med. 2026 Jun 5;13:1776637. doi: 10.3389/fcvm.2026.1776637. eCollection 2026.
PubMed 42325689Jastrzebski M, Moskal P, Huybrechts W, Curila K, Sreekumar P, Rademakers LM, Ponnusamy SS, Herweg B, Sharma PS, Bednarek A, Rajzer M, Vijayaraman P. Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT): Results from an international LBBAP collaborative study group. Heart Rhythm. 2022 Jan;19(1):13-21. doi: 10.1016/j.hrthm.2021.07.057. Epub 2021 Jul 30.
PubMed 34339851Leventopoulos G, Nastouli KM, Bozika M, Papastavrou E, Apostolos A, Koros R, Perperis A, Koniari I, Vlassopoulou N, Chronopoulos P, Travlos CK, Moulias A, Davlouros P. Understanding LOT-CRT: Current Insights, Limitations, and Our Center's Experience. J Clin Med. 2025 Apr 27;14(9):3025. doi: 10.3390/jcm14093025.
PubMed 40364057Ezer P, Szucs K, Lukacs R, Bisztray T, Vilmanyi G, Szokodi I, Komocsi A, Konyi A. The Suboptimal QLV Ratio May Indicate the Need for a Left Bundle Branch Area Pacing-Optimized Cardiac Resynchronization Therapy Upgrade. J Clin Med. 2024 Sep 26;13(19):5742. doi: 10.3390/jcm13195742.
PubMed 39407802
Study at a glance
From the registry record, last updated by the sponsor on 10 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- REstoration of SYNChronous Cardiac Function Due to Physiologic cArdiac Pacing Modalities With Clinical Endpoints RESYNC-PACE
- ClinicalTrials.gov ID
- NCT07684547
- Acronym / sponsor ID
- RESYNC-PACE / FF107 RESYNC-PACE ver1.0
- Conditions
- Heart Failure - NYHA II - IV, Left Bundle Branch Area Pacing, Left Bundle Branch Block, Intraventricular Conduction Delay, Resynchronization Therapy
- Keywords
- carrdiac resynchornization therapy, Physiologic Pacing, Conduction System Pacing, Electrical Resynchronization, Physiologic CRT
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- University of PecsUniversity, hospital or other
- Collaborators
- Medical University of Pecs
- Study start
- 29 Jun 2026 (estimated)
- Primary completion
- 29 Jun 2030 (estimated)
- Study completion
- 29 Jun 2031 (estimated)
- First posted
- 6 Jul 2026 (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.
The goal of this observational study is to evaluate the long-term clinical outcomes of physiologic cardiac resynchronization therapy (CRT) using conduction system pacing strategies compared with conventional biventricular CRT in patients with heart failure with reduced ejection fraction (HFrEF) and electrical dyssynchrony.
The main questions it aims to answer are:
- Does physiologic CRT (including left bundle branch area pacing [LBBAP] and LBBAP-optimized CRT) reduce the combined risk of all-cause mortality and heart failure hospitalization compared with conventional biventricular CRT?
- Does physiologic CRT improve cardiac function and reverse ventricular remodeling more effectively than conventional CRT?
Participants receiving physiologic CRT as part of routine clinical care will undergo standard follow-up evaluations, including electrocardiography, echocardiography, laboratory testing, and device interrogation. Clinical outcomes will be collected prospectively for 24 months and compared with a historical cohort of patients treated with conventional biventricular CRT.
The study will assess clinical outcomes, echocardiographic response, electrical resynchronization parameters, and device-related safety in a real-world heart failure population.
Detailed description
Background
Heart failure with reduced ejection fraction (HFrEF) is associated with substantial morbidity, mortality, and healthcare utilization despite continuous advances in guideline-directed medical therapy. Cardiac resynchronization therapy (CRT) has become an established treatment for patients with symptomatic HFrEF and electrical dyssynchrony. Conventional biventricular pacing improves ventricular synchrony and clinical outcomes; however, approximately one-third of treated patients do not achieve a satisfactory response.
Conduction system pacing (CSP), particularly left bundle branch area pacing (LBBAP), has emerged as a physiological pacing strategy capable of directly engaging the native His-Purkinje conduction system. Compared with conventional biventricular pacing, CSP may produce more physiological ventricular activation, narrower paced QRS complexes, improved electrical synchrony, and greater reverse ventricular remodeling. Nevertheless, evidence regarding its long-term effectiveness in routine clinical practice remains limited, particularly in heterogeneous populations with different conduction abnormalities.
Study Rationale
The RESYNC-PACE study was designed to evaluate the effectiveness of individualized physiologic cardiac resynchronization strategies in a real-world population of patients with HFrEF requiring CRT.
The study investigates two complementary physiologic CRT approaches according to the underlying conduction disturbance. In patients with typical left bundle branch block (LBBB), left ventricular lead implantation is guided by the qLV ratio to achieve optimal electrical resynchronization through individualized coronary sinus lead positioning. In patients with intraventricular conduction delay (IVCD), a conduction system pacing strategy is applied using left bundle branch area pacing. When conduction system pacing alone results in incomplete electrical correction, defined by a paced QRS duration greater than 130 ms, an additional coronary sinus left ventricular lead is implanted to establish Left Bundle Branch Area Pacing Optimized Cardiac Resynchronization Therapy (LOT-CRT).
This individualized treatment algorithm reflects contemporary physiological concepts of ventricular resynchronization rather than a single implantation strategy and represents the principal scientific concept investigated in the study.
Scientific Objectives
The study aims to determine whether physiologic CRT strategies provide superior long-term clinical outcomes compared with conventional biventricular CRT when implemented in routine clinical practice.
In addition to evaluating clinical outcomes, the study investigates the relationship between electrical resynchronization, ventricular reverse remodeling, myocardial scar characteristics assessed by cardiac magnetic resonance imaging, and long-term prognosis. Particular emphasis is placed on identifying imaging-, electrocardiographic-, and device-derived predictors of CRT response that may facilitate patient selection and optimization of resynchronization therapy.
Study Methodology
RESYNC-PACE is a single-center, ambispective observational cohort study performed at the University of Pécs Clinical Centre Heart Institute. Consecutive patients undergoing physiologic CRT constitute the prospective cohort, while a historical cohort of patients treated with conventional biventricular CRT serves as the comparator.
All therapeutic procedures are performed as part of routine clinical care using commercially available CE-marked cardiac implantable electronic devices according to their approved indications and current international guideline recommendations. The study does not introduce experimental devices or procedures beyond standard clinical practice but prospectively evaluates the clinical performance of an individualized physiological CRT algorithm.
The comprehensive study database integrates demographic, clinical, electrocardiographic, echocardiographic, cardiac magnetic resonance imaging, procedural, device-derived, and long-term follow-up data. This integrated approach enables detailed evaluation of the mechanisms underlying CRT response and supports the development of patient-specific resynchronization strategies.
Expected Clinical Significance
The RESYNC-PACE study is expected to generate real-world evidence regarding the effectiveness of conduction system pacing-guided CRT strategies and individualized resynchronization algorithms. The findings may improve patient selection, optimize implantation strategies for different conduction disorders, and contribute to the growing evidence supporting physiologic cardiac resynchronization therapy in patients with heart failure.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 24 Months
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Left bundle branch block patients | – | Device: Physiologic cardiac resynchronization using conduction system pacing and selective LV lead optimization.LBBB Cohort (qLV-guided Cardiac Resynchronization Therapy) Patients in this cohort have symptomatic heart failure with reduced left ventricular ejection fraction and complete left bundle branch block (LBBB) according to contemporary guideline criteria. Cardiac resynchronization therapy is performed using a personalized implantation strategy guided by the qLV ratio, defined as the interval between QRS onset and local left ventricular activation divided by the intrinsic QRS duration. The left ventricular lead is positioned at the site with the longest achievable electrical delay to maximize resynchronization benefit. Patients receive either conventional biventricular CRT or LOT- CRT according to clinical decision-making and anatomical feasibility. The cohort is followed longitudinally to evaluate the relationship between qLV-guided lead placement, electrical resynchronization, reverse ventricular remodeling, heart failure hospitalization, and all-cause mortality. |
| Intraventricular conduction delay patients | – | Device: Physiologic cardiac resynchronization using conduction system pacing and selective LV lead optimization.IVCD Cohort (Conduction System Pacing-Guided Resynchronization Strategy) Patients in this cohort have symptomatic heart failure with reduced left ventricular ejection fraction and intraventricular conduction delay (IVCD) without typical left bundle branch block morphology. The resynchronization strategy is guided by the degree of electrical correction achieved with conduction system pacing. During implantation, left bundle branch area pacing (LBBAP) is attempted and paced QRS duration is assessed. If conduction system pacing alone results in a paced QRS duration greater than 130 ms, a Left Bundle Branch Area Pacing Optimized Cardiac Resynchronization Therapy (LOT-CRT) system is implanted by adding a left ventricular lead to further improve ventricular synchrony. The cohort is followed longitudinally to evaluate the association between electrical resynchronization, reverse ventricular remodeling, heart failure hospitalization, and all-cause mortality. |
Who may qualify
- Ages
- 18 to 100 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population consists of adult patients with heart failure with reduced ejection fraction (HFrEF) who are treated at the University of Pécs Clinical Centre Heart Institute and meet contemporary guideline indications for cardiac resynchronization therapy (CRT). Eligible participants have symptomatic heart failure despite guideline-directed medical therapy, left ventricular systolic dysfunction, and evidence of electrical dyssynchrony manifested by left bundle branch block (LBBB) or intraventricular conduction delay (IVCD). The prospective cohort includes patients undergoing conduction system pacing-based CRT as part of routine clinical care, while the historical control cohort includes patients previously treated with conventional biventricular CRT at the same institution. The study population represents a real-world heart failure population routinely referred for CRT implantation in tertiary cardiovascular care.
Key inclusion criteria (9 listed)
- Age ≥18 years.
- Symptomatic heart failure despite guideline-directed medical therapy.
- Left ventricular ejection fraction (LVEF) ≤40%.
- Indication for cardiac resynchronization therapy according to contemporary ESC guideline recommendations.
- QRS duration ≥150 ms with either:
Key exclusion criteria (10 listed)
- Age <18 years and Age 100 < years
- Pregnancy or breastfeeding.
- Inability or unwillingness to provide informed consent.
- Life expectancy <12 months due to non-cardiac comorbidities.
- Active systemic infection or infection involving a cardiac implantable electronic device.
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 |
|---|---|---|
| Physiologic cardiac resynchronization using conduction system pacing and selective LV lead optimization.Also: Cardiac resynchronization therapy using left bundle branch area pacing with or without LV lead optimization., Cardiac resynchronization guided by conduction system pacing to improve ventricular synchrony.Conduction System Pacing-Guided Cardiac Resynchronization Therapy is an individualized resynchronization strategy used in patients with heart failure, reduced left ventricular ejection fraction, and electrical dyssynchrony. The intervention is based on direct recruitment of the native cardiac conduction system through left bundle branch area pacing (LBBAP). During implantation, electrical resynchronization is assessed using electrocardiographic and device-derived parameters. In patients with intraventricular conduction delay or incomplete electrical correction, additional left ventricular pacing may be provided using a coronary sinus lead, resulting in Left Bundle Branch Area Pacing Optimized Cardiac Resynchronization Therapy (LOT-CRT). The intervention aims to achieve more physiological ventricular activation than conventional biventricular pacing, improve electrical synchrony, promote reverse ventricular remodeling, and reduce heart failure-related adverse events. | Device | Intraventricular conduction delay patients, Left bundle branch block patients |
Primary outcome
Composite of All-Cause Mortality and Heart Failure Hospitalization
Time frame: 24 months
Time to first occurrence of the composite endpoint of all-cause mortality or hospitalization due to worsening heart failure during the 24-month follow-up period.
4 secondary outcomes
Change in Left Ventricular Ejection Fraction (LVEF)
Time frame: Baseline to 24 months
Change in Left Ventricular End-Systolic Volume ( LV ESV)
Time frame: Baseline to 24 months
Change in paced QRS Duration
Time frame: Baseline to 24 months
New York Heart Association Heart Failure Functional Status
Time frame: Baseline to 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 10 Jul 2026.
- Background: PubMed 42325689Guo J, Luo W, Zhao S, Cui H, Wang X, Li X. Conduction system pacing compared with biventricular pacing for cardiac resynchronization therapy: a systematic review and meta-analysis. Front Cardiovasc Med. 2026 Jun 5;13:1776637. doi: 10.3389/fcvm.2026.1776637. eCollection 2026.
- Background: PubMed 34339851Jastrzebski M, Moskal P, Huybrechts W, Curila K, Sreekumar P, Rademakers LM, Ponnusamy SS, Herweg B, Sharma PS, Bednarek A, Rajzer M, Vijayaraman P. Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT): Results from an international LBBAP collaborative study group. Heart Rhythm. 2022 Jan;19(1):13-21. doi: 10.1016/j.hrthm.2021.07.057. Epub 2021 Jul 30.
- Background: PubMed 40364057Leventopoulos G, Nastouli KM, Bozika M, Papastavrou E, Apostolos A, Koros R, Perperis A, Koniari I, Vlassopoulou N, Chronopoulos P, Travlos CK, Moulias A, Davlouros P. Understanding LOT-CRT: Current Insights, Limitations, and Our Center's Experience. J Clin Med. 2025 Apr 27;14(9):3025. doi: 10.3390/jcm14093025.
- Background: PubMed 39407802Ezer P, Szucs K, Lukacs R, Bisztray T, Vilmanyi G, Szokodi I, Komocsi A, Konyi A. The Suboptimal QLV Ratio May Indicate the Need for a Left Bundle Branch Area Pacing-Optimized Cardiac Resynchronization Therapy Upgrade. J Clin Med. 2024 Sep 26;13(19):5742. doi: 10.3390/jcm13195742.
- Individual participant dataSharing planned: Undecided. ndividual participant data will be shared only in a de-identified form and in accordance with applicable data protection regulations, institutional policies, and informed consent provisions. Data sharing may be limited where participant privacy, ethical considerations, or legal requirements prevent full disclosure of individual-level data.
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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?
An observational study of Heart Failure - NYHA II - IV and Left Bundle Branch Area Pacing, run by University of Pecs at 1 site in Hungary.
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 9 inclusion and 10 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: opening soon, as of the sponsor's last update on 10 Jul 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 Hungary. 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 Peter Ezer MD PhD, assistant professor (+36305468840, ezerpeti@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Composite of All-Cause Mortality and Heart Failure Hospitalization (time frame: 24 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07684547, which also lists 4 linked publications.
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 10 Jul 2026.