Left Bundle-Branch BlockFLOW-LBBBNCT05564689
Absolute Coronary Flow in Patients With Heart Failure With Reduced Ejection Fraction and Left Bundle Branch Block With Cardiac Resynchronization Therapy
An observational study of Left Bundle-Branch Block and Heart Failure, run by Ashkan Eftekhari at 1 site in Denmark.
Trial summary
Cardiac resynchronization therapy (CRT) is an effective therapeutic strategy in patients with symptomatic heart failure (HF) patients with LVEF of ≤35% and left bundle branch block (LBBB). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Left Bundle-Branch Block, Heart Failure, Cardiac Resynchronization Therapy
- What is being tested?
- Intracoronary flow and pressure
- Type of treatment
- Surgery or procedure
- How many people
- 60 participants
- Where
- 1 siteDenmark
- Study dates
- 29 Sep 2022to 30 Sep 2026
- 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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study will include patients with heart failure due to non ischemic dilated cardiomyopathy and LBBB, with or without excisting CRT. Eligible patients who are admitted to the Department of Cardiology or at a visit to the outpatient clinic at the Dept. Cardiology Aalborg University Hospital will be enrolled in the study.
Who may be able to join
- Age > 18
- QRS ≥ 150 ms before implantation
- Heart failure because of dilated cardiomypathy
- Sinus rhythm
- Stable medical therapy
- LBBB
- CRT device
Who cannot join
- eGFR < 30 ml/min
- Severe valvular heart disease
- Permanent atrial fibrillation or atrial flutter
- Prior PCI or CABG
- Prior myocardial infarction
- Heart failure due to ischemic heart disease
Show all 9Show fewer
- Other type of device (pacemaker, ICD)
- Not able to give informed consent
- Does not understand Danish
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Denmark1 site, 1 recruiting
- Recruiting
Aalborg Universityhospital
Aalborg, 9000
Ashkan Eftekhari, asef@rn.dk
Sanna Gunnarstein, 42918950, s.gunnarstein@rn.dk
About this study
Cardiac resynchronization therapy (CRT) is an effective therapeutic strategy in patients with symptomatic heart failure (HF) patients with LVEF of ≤35% and left bundle branch block (LBBB). However, approximately one-third of CRT-recipients do not improve after therapy (non-responders), despite meeting the required criteria.
Previous studies have documented that the positive respons to CRT is related to the delayed electrical activation of the left ventricle in patients with LBBB. It has also been illustrated that non-ischemic CRT-candidates with LBBB demonstrate lower regional myocardial blood flow and metabolism in the septum. Additionally, it has been suggested that LBBB can lead to impaired coronary blood flow in the left anterior descending artery (LAD). This observation is based on an echocardiography-based study, that showed that the percentage of diastolic flow duration (%DD) in LAD was shorter in patients with LBBB compared to the control-group and patients with right-ventricular pacing.
Read more
It has been demonstrated that CRT has positive effects on septal myocardial perfusion in patients with HF and LBBB. The dominant hypothesis explaining this phenomenon is built on improved septal myocardial work after CRT-implantation, which leads to increased myocardial energy and therefore increased myocardial perfusion. In contrast, it has been suggested that due to re-established synchronous left ventricular electrical activation, CRT reduces the septal intramyocardial pressure in early diastole, leading to a relatively longer antegrade flow duration in LAD. Therefore, the aim of the study is to evaluate the effect of CRT on coronary blood flow in LAD in patients with non-ischemic HF and LBBB.
The investigators hypothesize that increased LV-function after CRT not only is due to resynchronized LV ejection and filling, but also improved coronary flow.
The study aims to enroll 60 patients with heart failure due to non-ischemic dilated cardiomyopathy, LBBB, with or without CRT. All patients meeting the criteria will be recruited from the outpatient clinic at the Department of Cardiology, Aalborg University Hospital.
Invasive flow measurements in the LAD, including fractional flow reserve (FFR), absolute coronary flow and -reserve will be conducted with the CRT on and off, respectively.
- Conditions
- Left Bundle-Branch Block, Heart Failure, Cardiac Resynchronization Therapy, Dilated Cardiomyopathy
- Being tested
- Intracoronary flow and pressure
- Keywords
- absolute coronary flow, fractional flow reserve
- Medical subject headings
- Bundle-Branch Block, Heart Failure, Cardiomyopathy, Dilated
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Intracoronary flow and pressureProcedure or surgery
Measurement of absolute coronary flow and resistance
| Study group | Role | What they receive |
|---|---|---|
| Patients with or in need of CRT, left bundle branch block, without ischemic heart disease | Not described Receives: Procedure: Intracoronary flow and pressure |
What is being measured
The primary outcome is the main question the study is designed to answer.
Absolute coronary flow
Measurement of absolute coronary flow with/without CRT-function
Measured: During procedure
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Oct 2022
- Study start29 Sep 2022
- Primary completion30 Sep 2026 (estimated)
- Study completion30 Sep 2026 (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
- Observational
- Observational model
- Case only
- Time perspective
- Other
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ashkan Eftekhari
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Ashkan Eftekhari, Aalborg University Hospital
- Investigators
- Ashkan Eftekhari, Principal investigator, Department of Cardiology, Aalborg University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05564689
- Sponsor's protocol ID
- N-20220040
- Acronym
- FLOW-LBBB
- Status last verified
- Jun 2025
- First submitted
- 29 Sep 2022
- Last updated
- 18 Jun 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 18 Jun 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Absolute Coronary Flow in Patients With Heart Failure With Reduced Ejection Fraction and Left Bundle Branch Block With Cardiac Resynchronization Therapy
- ClinicalTrials.gov ID
- NCT05564689
- Acronym / sponsor ID
- FLOW-LBBB / N-20220040
- Conditions
- Left Bundle-Branch Block, Heart Failure, Cardiac Resynchronization Therapy, Dilated Cardiomyopathy
- Keywords
- absolute coronary flow, fractional flow reserve
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Ashkan EftekhariUniversity, hospital or other
- Study start
- 29 Sep 2022 (actual)
- Primary completion
- 30 Sep 2026 (estimated)
- Study completion
- 30 Sep 2026 (estimated)
- First posted
- 3 Oct 2022 (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.
Cardiac resynchronization therapy (CRT) is an effective therapeutic strategy in patients with symptomatic heart failure (HF) patients with LVEF of ≤35% and left bundle branch block (LBBB). However, approximately one-third of CRT-recipients do not improve after therapy (non-responders), despite meeting the required criteria.
Previous studies have documented that the positive respons to CRT is related to the delayed electrical activation of the left ventricle in patients with LBBB. It has also been illustrated that non-ischemic CRT-candidates with LBBB demonstrate lower regional myocardial blood flow and metabolism in the septum. Additionally, it has been suggested that LBBB can lead to impaired coronary blood flow in the left anterior descending artery (LAD). This observation is based on an echocardiography-based study, that showed that the percentage of diastolic flow duration (%DD) in LAD was shorter in patients with LBBB compared to the control-group and patients with right-ventricular pacing.
It has been demonstrated that CRT has positive effects on septal myocardial perfusion in patients with HF and LBBB. The dominant hypothesis explaining this phenomenon is built on improved septal myocardial work after CRT-implantation, which leads to increased myocardial energy and therefore increased myocardial perfusion. In contrast, it has been suggested that due to re-established synchronous left ventricular electrical activation, CRT reduces the septal intramyocardial pressure in early diastole, leading to a relatively longer antegrade flow duration in LAD. Therefore, the aim of the study is to evaluate the effect of CRT on coronary blood flow in LAD in patients with non-ischemic HF and LBBB.
The investigators hypothesize that increased LV-function after CRT not only is due to resynchronized LV ejection and filling, but also improved coronary flow.
The study aims to enroll 60 patients with heart failure due to non-ischemic dilated cardiomyopathy, LBBB, with or without CRT. All patients meeting the criteria will be recruited from the outpatient clinic at the Department of Cardiology, Aalborg University Hospital.
Invasive flow measurements in the LAD, including fractional flow reserve (FFR), absolute coronary flow and -reserve will be conducted with the CRT on and off, respectively.
Study design
- Observational model
- Case only
- Time perspective
- Other
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Patients with or in need of CRT, left bundle branch block, without ischemic heart disease | – | Procedure: Intracoronary flow and pressure |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study will include patients with heart failure due to non ischemic dilated cardiomyopathy and LBBB, with or without excisting CRT. Eligible patients who are admitted to the Department of Cardiology or at a visit to the outpatient clinic at the Dept. Cardiology Aalborg University Hospital will be enrolled in the study.
Key inclusion criteria (7 listed)
- Age > 18
- QRS ≥ 150 ms before implantation
- Heart failure because of dilated cardiomypathy
- Sinus rhythm
- Stable medical therapy
Key exclusion criteria (9 listed)
- eGFR < 30 ml/min
- Severe valvular heart disease
- Permanent atrial fibrillation or atrial flutter
- Prior PCI or CABG
- Prior myocardial infarction
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 |
|---|---|---|
| Intracoronary flow and pressureMeasurement of absolute coronary flow and resistance | Procedure or surgery | Patients with or in need of CRT, left bundle branch block, without ischemic heart disease |
Primary outcome
Absolute coronary flow
Time frame: During procedure
Measurement of absolute coronary flow with/without CRT-function
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 18 Jun 2025.
- Individual participant dataSharing planned: Undecided
Related trials for Left Bundle-Branch Block
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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.
Ashkan Eftekhari principal investigator
Department of Cardiology, Aalborg University Hospital
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 Left Bundle-Branch Block and Heart Failure, run by Ashkan Eftekhari at 1 site in Denmark.
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 9 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 18 Jun 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 Denmark. 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 Ashkan Eftekhari (004528973764, asef@rn.dk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Absolute coronary flow (time frame: During procedure). 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 18 Jun 2025.