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RecruitingNCT07057544UHF BLOCKUpdated Jul 14, 2025

UHF ECG in LBBB and Response to CRT Prediction

An interventional study of LBBAP CRT device implantation and BVP-CRT in Left Bundle Branch Block, Left Bundle Branch Area Pacing and Biventricular Pacing, sponsored by Faculty Hospital Kralovske Vinohrady. Recruiting at 1 site in Czechia. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-07-14.

Sponsored by Faculty Hospital Kralovske Vinohrady · Not applicable, Interventional, and Treatment

From the registry’s dates

  • Registered 1 year 1 month after the study started (first participant enrolled May 2024, registered Jun 2025).
  • Started May 2024; still recruiting 2 years 6 months later.
Phase
Not applicable
Study type
Interventional
Enrollment
200
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study 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.

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.

02

Conditions studied

  • Left Bundle Branch Block
  • Left Bundle Branch Area Pacing
  • Biventricular Pacing
  • Intraventricular Conduction Delay

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Keywords

  • left bundle branch block
  • resynchronization therapy
  • intraventricular conduction delay
  • left bundle branch pacing
  • biventricular pacing
03

In context

Bundle-Branch Block

94 studies on the registry are indexed under Bundle-Branch Block; 30 are open to participants now.

This study's planned enrollment of 200 is above the median of 60 across 59 interventional studies indexed under Bundle-Branch Block.

Browse Bundle-Branch Block studies →

Lead sponsor

Faculty Hospital Kralovske Vinohrady is the lead sponsor of 30 studies on the registry; 6 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • HF due to ischemic or non-ischemic cardiomyopathy
  • known coronary angiography
  • II-IV
  • ≤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

Exclusion criteria

Exclusion Criteria:

  • Age ˂18 years
  • heart failure from reversible causes
  • Moderate to severe aortic stenosis
  • pregnancy
  • active myocarditis
  • hypertrophic cardiomyopathy
  • 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
  • ˂1 year
  • known medical condition or causing potential complications for EP study
Terms in these criteria, in plain language(4)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

NYHA class (heart failure)

The New York Heart Association’s four classes of how much heart failure limits physical activity.

I
No limits: ordinary activity causes no undue tiredness or breathlessness.
II
Slight limits: comfortable at rest, ordinary activity causes symptoms.
III
Marked limits: comfortable at rest, less than ordinary activity causes symptoms.
IV
Symptoms even at rest; any activity makes them worse.

Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.

LVEF (left ventricular ejection fraction)

The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.

Life expectancy

The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.

Contraindication

A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.

05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Single (Participant)
Enrollment
200 participants (estimated)

Study arms

  • Experimental
    CSP-CRT arm

    In this arm, LBBAP CRT will be performed

    Device: LBBAP CRT device implantation

  • Active comparator
    BVP-CRT arm

    In this arm, BVP CRT will be performed.

    Device: BVP-CRT

Interventions

  • DeviceLBBAP CRT device implantation

    Pacing system with a lead implanted in the left bundle branch area will be done.

  • DeviceBVP-CRT

    Implantation of biventricular device

06

What researchers measure

Primary outcomes

  1. Left ventricular end-systolic volume

    Left ventricular end-systolic volume reduction

    Time frame: 6 and 18 months since randomization

07

Study locations

1 of 1 sites recruiting
08

References and documents

Individual participant data

Plan to share: Undecided

No publications or documents are linked to this record.

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Started May 2024 (actual). Primary completion is estimated for Dec 2027, 43 months after the start.

Of 32 interventional studies with no phase under Bundle-Branch Block, half reached primary completion within 50 months of starting (the median), counting those still running; a quarter within 33 and three quarters within 61. This study's planned 43 months is below that.

How these figures are worked out, and which studies are left out of them.

Registered
Jun 30, 2025
First posted
Jul 10, 2025
StartActual
May 1, 2024
Primary completionEst.
Dec 31, 2027
CompletionEst.
Dec 31, 2027
Last update
Jul 14, 2025
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Jul 14, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT07057544
Lead sponsor
Faculty Hospital Kralovske Vinohrady
Responsible party
Karol Curila (MD, PhD, Faculty Hospital Kralovske Vinohrady) — Principal investigator
First posted
Jul 10, 2025
Start date
May 1, 2024
Primary completion
Dec 31, 2027 (estimated)
Completion
Dec 31, 2027 (estimated)
Last update
Jul 14, 2025

Study contacts

Karol Curila, MD
Contact
karol.curila@fnkv.cz
+420777869171

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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