Left Bundle Branch BlockUHF BLOCKNCT07057544
UHF ECG in LBBB and Response to CRT Prediction
A study testing LBBAP CRT device implantation and BVP-CRT in people with Left Bundle Branch Block and Left Bundle Branch Area Pacing, run by Faculty Hospital Kralovske Vinohrady at 1 site in Czechia.
Trial summary
The main objective of the project is to demonstrate that in patients with heart failure and QRS complex of nonRBBB morphology lasting over 130 ms, UHF-ECG can differentiate patients with trueLBBB from IVCD better than existing approaches based on the assessment of QRS complex morphology and duration from 12-lead ECG. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Left Bundle Branch Block, Left Bundle Branch Area Pacing, Biventricular Pacing
- What is being tested?
- LBBAP CRT device implantation and BVP-CRT
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 200 participants
- Where
- 1 siteCzechia
- Study dates
- 1 May 2024to 31 Dec 2027
- 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
- HF due to ischemic or non-ischemic cardiomyopathy
- known coronary angiography
- NYHA II-IV
- LVEF ≤40%
- non-RBBB QRSd lasting >130 ms (by automated measurement)
- proximal LBBB proved by an invasive EP study or non-invasive dyssynchrony assessment in case such a method is confirmed to be non-inferior to an invasive EP study during the project
Who cannot join
- Age ˂18 years
- heart failure from reversible causes
- Moderate to severe aortic stenosis
- pregnancy
- active myocarditis
- hypertrophic cardiomyopathy
Show all 12Show fewer
- cardiac valve surgery in the last three months
- myocardial infarction, PCI, or CABG in the last three months
- severe valvular disease requiring intervention
- severe atherosclerotic disease of the aorta and/or femoral arteries
- life expectancy ˂1 year
- known medical condition or contraindication causing potential complications for EP study
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Czechia1 site, 1 recruiting
- Recruiting
Faculty Hospital Kralovske Vinohrady
Prague, Česká Republika, 10034
Karol Curila, +420777869171, karol.curila@fnkv.cz
About this study
Official title: The Role of Ultra-high-frequency ECG in the Localization of Left Ventricular Conduction Disorders and Prediction of Response to Resynchronization Therapy
The main objective of the project is to demonstrate that in patients with heart failure and QRS complex of nonRBBB morphology lasting over 130 ms, UHF-ECG can differentiate patients with trueLBBB from IVCD better than existing approaches based on the assessment of QRS complex morphology and duration from 12-lead ECG.
Another goal of the proposed study is to demonstrate that trueLBBB patients will benefit more from CRT using left bundle branch pacing than from CRT using biventricular pacing.
The final aim of the project is to demonstrate that the echocardiographic and clinical response in patients with intraventricular conduction disturbance will be dependent on the degree of reduction in ventricular dyssynchrony after CRT.
Read the detailed description
Since the introduction of cardiac resynchronization therapy (CRT), a way to better define the patients who will benefit from it most has been sought. Their selection based on the duration of the QRS complex or its morphology fails in some of them. Current data demonstrate that CRT done by pacing the conduction system below the site of the left bundle branch block may be a better therapy than biventricular pacing. A prerequisite for a better effect of conduction system pacing is to perform it in patients in whom a conduction block is present in the left bundle branch block ("true" LBBB) and not in the patients with a more distal left ventricular conduction problem (IVCD). The criteria derived from the surface standard ECG are insufficient to differentiate "true" LBBB from IVCD, and thus it is not possible to determine the optimal treatment in some patients. The sequence of ventricular activation can be visualized within a few minutes using ultra-highfrequency ECG (UHF-ECG) in virtually all patients. It is a non-invasive method that shows ventricular dyssynchrony as a time difference between the activation of the ventricles or their individual segments. Pilot data show that patients with "true" LBBB are likely to have greater ventricular dyssynchrony and a different pattern of ventricular depolarization than patients with IVCD. The aim of this project is to test the hypothesis that UHF-ECG can distinguish "true" LBBB from IVCD in patients with heart failure and left ventricular conduction disturbance better than using standard criteria assessing QRS duration and morphology. Other aim is to demonstrate that in patients with trueLBBB resynchronization using conduction system pacing will lead to better echocardiographic and clinical outcomes than biventricular pacing. Finally, the echocardiographic and clinical response of IVCD patients will depend on the reduction of UHF-ECG ventricular dyssynchrony after CRT.
- Conditions
- Left Bundle Branch Block, Left Bundle Branch Area Pacing, Biventricular Pacing, Intraventricular Conduction Delay
- Being tested
- LBBAP CRT device implantation, BVP-CRT
- Keywords
- left bundle branch block, resynchronization therapy, intraventricular conduction delay, left bundle branch pacing, biventricular pacing
- 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.
LBBAP CRT device implantationDevice
Pacing system with a lead implanted in the left bundle branch area will be done.
BVP-CRTDevice
Implantation of biventricular device
| Study group | Role | What they receive |
|---|---|---|
| CSP-CRT arm | Experimental | In this arm, LBBAP CRT will be performed Receives: Device: LBBAP CRT device implantation |
| BVP-CRT arm | Active comparator | In this arm, BVP CRT will be performed. Receives: Device: BVP-CRT |
What is being measured
The primary outcome is the main question the study is designed to answer.
Left ventricular end-systolic volume
Left ventricular end-systolic volume reduction
Measured: 6 and 18 months since randomization
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Jul 2025
- Study start1 May 2024
- Primary completion31 Dec 2027 (estimated)
- Study completion31 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Left Bundle Branch BlockStudies 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
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Faculty Hospital Kralovske Vinohrady
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Karol Curila, Faculty Hospital Kralovske Vinohrady
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07057544
- Sponsor's protocol ID
- UHFBLOCK trial
- Other IDs
- NW24-02-00143
- Acronym
- UHF BLOCK
- Status last verified
- Jul 2025
- First submitted
- 30 Jun 2025
- Last updated
- 14 Jul 2025
- Results posted
- No
- Data monitoring committee
- No
- 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 14 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Role of Ultra-high-frequency ECG in the Localization of Left Ventricular Conduction Disorders and Prediction of Response to Resynchronization Therapy
- ClinicalTrials.gov ID
- NCT07057544
- Acronym / sponsor ID
- UHF BLOCK / UHFBLOCK trial
- Conditions
- Left Bundle Branch Block, Left Bundle Branch Area Pacing, Biventricular Pacing, Intraventricular Conduction Delay
- Keywords
- left bundle branch block, resynchronization therapy, intraventricular conduction delay, left bundle branch pacing, biventricular pacing
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- Faculty Hospital Kralovske VinohradyOther government
- Study start
- 1 May 2024 (actual)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 31 Dec 2027 (estimated)
- First posted
- 10 Jul 2025 (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 main objective of the project is to demonstrate that in patients with heart failure and QRS complex of nonRBBB morphology lasting over 130 ms, UHF-ECG can differentiate patients with trueLBBB from IVCD better than existing approaches based on the assessment of QRS complex morphology and duration from 12-lead ECG.
Another goal of the proposed study is to demonstrate that trueLBBB patients will benefit more from CRT using left bundle branch pacing than from CRT using biventricular pacing.
The final aim of the project is to demonstrate that the echocardiographic and clinical response in patients with intraventricular conduction disturbance will be dependent on the degree of reduction in ventricular dyssynchrony after CRT.
Detailed description
Since the introduction of cardiac resynchronization therapy (CRT), a way to better define the patients who will benefit from it most has been sought. Their selection based on the duration of the QRS complex or its morphology fails in some of them. Current data demonstrate that CRT done by pacing the conduction system below the site of the left bundle branch block may be a better therapy than biventricular pacing. A prerequisite for a better effect of conduction system pacing is to perform it in patients in whom a conduction block is present in the left bundle branch block ("true" LBBB) and not in the patients with a more distal left ventricular conduction problem (IVCD). The criteria derived from the surface standard ECG are insufficient to differentiate "true" LBBB from IVCD, and thus it is not possible to determine the optimal treatment in some patients. The sequence of ventricular activation can be visualized within a few minutes using ultra-highfrequency ECG (UHF-ECG) in virtually all patients. It is a non-invasive method that shows ventricular dyssynchrony as a time difference between the activation of the ventricles or their individual segments. Pilot data show that patients with "true" LBBB are likely to have greater ventricular dyssynchrony and a different pattern of ventricular depolarization than patients with IVCD. The aim of this project is to test the hypothesis that UHF-ECG can distinguish "true" LBBB from IVCD in patients with heart failure and left ventricular conduction disturbance better than using standard criteria assessing QRS duration and morphology. Other aim is to demonstrate that in patients with trueLBBB resynchronization using conduction system pacing will lead to better echocardiographic and clinical outcomes than biventricular pacing. Finally, the echocardiographic and clinical response of IVCD patients will depend on the reduction of UHF-ECG ventricular dyssynchrony after CRT.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| CSP-CRT arm | Experimental | Device: LBBAP CRT device implantationIn this arm, LBBAP CRT will be performed |
| BVP-CRT arm | Active comparator | Device: BVP-CRTIn this arm, BVP CRT will be performed. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- HF due to ischemic or non-ischemic cardiomyopathy
- known coronary angiography
- NYHA II-IV
- LVEF ≤40%
- non-RBBB QRSd lasting >130 ms (by automated measurement)
Key exclusion criteria (12 listed)
- Age ˂18 years
- heart failure from reversible causes
- Moderate to severe aortic stenosis
- pregnancy
- active myocarditis
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 |
|---|---|---|
| LBBAP CRT device implantationPacing system with a lead implanted in the left bundle branch area will be done. | Device | CSP-CRT arm |
| BVP-CRTImplantation of biventricular device | Device | BVP-CRT arm |
Primary outcome
Left ventricular end-systolic volume
Time frame: 6 and 18 months since randomization
Left ventricular end-systolic volume reduction
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 14 Jul 2025.
- Individual participant dataSharing planned: Undecided
Related trials for Left Bundle Branch Block
Active, not recruiting
REsynchronization Comparison In LBBB and Normal or Mildly Reduced VENTricular Function With CRT (REINVENT-CRT)
Left Ventricular Ejection Fraction, Heart Failure (HF)
Recruiting
Ambulatory Electrocardiographic Monitoring for the Detection of High-Degree Atrio-Ventricular Block in Patients With New-onset PeRsistent LEft Bundle Branch Block After Transcatheter Aortic Valve Implantation. The "MARE" Study
Aortic Valve Disease, Conduction Disturbances
Not yet recruiting
LBBAP Versus ILR in Patients With New-Onset LBBB and Moderately Reduced LVEF After TAVI
TAVI(Transcatheter Aortic Valve Implantation), Left Bundle Branch Block
Active, not recruitingObservational study
Safety, Performance, and Clinical Benefit of Pacing the Left Bundle Branch Area - Post-Market Clinical Follow-up
Bradycardia, Atrioventricular Block
Recruiting
Advancing Clinical Heart Failure Outcomes Leveraging Defibrillation Lead Implant System for Left Bundle Branch Area Pacing
Heart Failure, Systolic Bundle Branch Block, Left
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 LBBAP CRT device implantation and BVP-CRT in people with Left Bundle Branch Block and Left Bundle Branch Area Pacing, run by Faculty Hospital Kralovske Vinohrady at 1 site in Czechia.
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 6 inclusion and 12 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 14 Jul 2025. 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 Czechia. 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 Karol Curila, MD (+420777869171, karol.curila@fnkv.cz), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Left ventricular end-systolic volume (time frame: 6 and 18 months since randomization). 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 14 Jul 2025.