Block Complete HeartNCT07812935
Closed-Loop Stimulation in Left Bundle Branch Area Pacing
A study testing Closed-Loop Stimulation and Accelerometer-Based VVIR Pacing in people with Block Complete Heart and Atrial Fibrillation (AF), run by Bartlomiej Wrobel at 1 site in Poland.
Trial summary
This prospective, single-center, crossover study evaluated the effects of closed-loop stimulation (CLS) compared with conventional accelerometer-based rate-adaptive pacing (VVIR) in patients with permanent atrial fibrillation undergoing left bundle branch area pacing (LBBAP). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Block Complete Heart, Atrial Fibrillation (AF), Chronotropic Incompetence
- What is being tested?
- Closed-Loop Stimulation and Accelerometer-Based VVIR Pacing
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 33 participants
- Where
- 1 sitePoland
- Study dates
- 23 Jun 2025to 27 Jul 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
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
- Permanent atrial fibrillation
- Chronotropic incompetence
- Permanent pacemaker with left bundle branch area pacing (LBBAP)
- Ventricular pacing burden >50%
- Ability to provide written informed consent
Who cannot join
- Age <18 years
- Inability or unwillingness to provide informed consent
Trial locations and contacts
1 site in 1 country.
Poland1 site
Clinical Provincial Hospital No. 2 in Rzeszow
Rzeszów, Podkarpackie Voivodeship, 35-302
About this study
Official title: Closed-Loop Stimulation Combined With Left Bundle Branch Area Pacing in Patients With Atrioventricular Conduction Disorders
This prospective, single-center, crossover study evaluated the effects of closed-loop stimulation (CLS) compared with conventional accelerometer-based rate-adaptive pacing (VVIR) in patients with permanent atrial fibrillation undergoing left bundle branch area pacing (LBBAP). Chronotropic responses were evaluated during standardized mental and physical stress testing. Heart rate distribution during daily activity, functional capacity, quality of life, and device-related parameters were also assessed.
- Being tested
- Closed-Loop Stimulation, Accelerometer-Based VVIR Pacing
- Keywords
- left bundle branch area pacing, closed loop stimulation, LBBAP, CLS, Rate adaptive pacing, cardiac pacing
- Medical subject headings
- Atrial Fibrillation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Closed-Loop StimulationDevice
The pacemaker was programmed to closed-loop stimulation (CLS), an impedance-based rate-adaptive pacing algorithm that adjusts the pacing rate in response to changes in intracardiac impedance associated with cardiac contractile dynamics.
Accelerometer-Based VVIR PacingDevice
The pacemaker was programmed to VVIR mode with accelerometer-based rate-adaptive pacing. The pacing rate was adjusted according to physical activity detected by the device's accelerometer.
| Study group | Role | What they receive |
|---|---|---|
| CLS followed by VVIR | Experimental | Participants received closed-loop stimulation (CLS) during the first study period, followed by accelerometer-based VVIR pacing during the second study period. Receives: Device: Closed-Loop Stimulation; Device: Accelerometer-Based VVIR Pacing |
| VVIR followed by CLS | Experimental | Participants received accelerometer-based VVIR pacing during the first study period, followed by closed-loop stimulation (CLS) during the second study period. Receives: Device: Closed-Loop Stimulation; Device: Accelerometer-Based VVIR Pacing |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Heart Rate During Mental Stress
Change in heart rate (ΔHR) during the Paced Auditory Serial Addition Test (PASAT), calculated as the peak heart rate recorded during the test minus the baseline heart rate. The outcome was assessed under both closed-loop stimulation (CLS) and accelerometer-based VVIR pacing and expressed in beats per minute (bpm).
Measured: At the end of each 1-month pacing period
Change in Heart Rate During Isometric Handgrip
Change in heart rate (ΔHR) during the 5-minute isometric handgrip test performed at 30% of maximal voluntary contraction, calculated as the peak heart rate recorded during the test minus the baseline heart rate. The outcome was assessed under both closed-loop stimulation (CLS) and accelerometer-based VVIR pacing and expressed in beats per minute (bpm).
Measured: At the end of each 1-month pacing period
Change in Heart Rate During Treadmill Exercise
Change in heart rate (ΔHR) during the symptom-limited treadmill exercise test using the modified Bruce protocol, calculated as the peak heart rate achieved during exercise minus the baseline heart rate. The outcome was assessed under both closed-loop stimulation (CLS) and accelerometer-based VVIR pacing and expressed in beats per minute (bpm).
Measured: At the end of each 1-month pacing period
Secondary outcomes (7)
Exercise Duration During Treadmill Testing
Total exercise duration during the symptom-limited treadmill exercise test performed using the modified Bruce protocol. The outcome was assessed under both closed-loop stimulation (CLS) and accelerometer-based VVIR pacing and expressed in seconds.
Measured: At the end of each 1-month pacing period
Metabolic Equivalents Achieved During Treadmill Testing
Exercise capacity during the symptom-limited treadmill exercise test using the modified Bruce protocol, expressed as metabolic equivalents (METs) achieved during the test. The outcome was assessed under both closed-loop stimulation (CLS) and accelerometer-based VVIR pacing.
Measured: At the end of each 1-month pacing period
Heart Rate Score During Daily Activity
Heart Rate Score (HRS), defined as the percentage of all sensed and paced ventricular beats occurring in the most populated 10-beats-per-minute heart rate histogram bin. HRS was assessed from pacemaker-derived heart rate histograms under both closed-loop stimulation (CLS) and accelerometer-based VVIR pacing. Higher HRS values indicate a more concentrated heart rate distribution and less heart rate variation across histogram bins. The score ranges from 0% to 100%.
Measured: At the end of each 1-month pacing period
Health-Related Quality of Life Assessed With the EQ-5D-5L Index
Health-related quality of life was assessed using the EuroQol 5-Dimension 5-Level (EQ-5D-5L) descriptive system. Responses were converted to an EQ-5D-5L index value using the Polish value set. Index values range from -0.590 to 1.000, with higher values indicating better health-related quality of life. A value of 1 represents full health, 0 represents a health state equivalent to death, and negative values represent health states valued as worse than death. The outcome was compared between closed-loop stimulation (CLS) and accelerometer-based VVIR pacing.
Measured: At the end of each 1-month pacing period
Self-Rated Health Assessed With the EQ VAS
Self-rated health was assessed using the EuroQol Visual Analogue Scale (EQ VAS), ranging from 0 to 100, where 0 represents the worst health the participant can imagine and 100 represents the best health the participant can imagine. The outcome was assessed under both closed-loop stimulation (CLS) and accelerometer-based VVIR pacing.
Measured: At the end of each 1-month pacing period
Patient-Reported Pacing-Mode Preference
At the end of the study, participants were asked during which of the two pacing periods they experienced better overall subjective well-being, or whether they had no preference. Responses were subsequently categorized according to the pacing mode programmed during the preferred period as preference for closed-loop stimulation (CLS), preference for accelerometer-based VVIR pacing, or no preference.
Measured: At the end of the study, after completion of both 1-month pacing periods
Ventricular Pacing Percentage
Ventricular pacing percentage was obtained from pacemaker interrogation and defined as the proportion of ventricular events that were paced during each study period. The outcome was assessed under both closed-loop stimulation (CLS) and accelerometer-based VVIR pacing and expressed as a percentage from 0% to 100%.
Measured: At the end of each 1-month pacing period
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Sep 2026
- Study start23 Jun 2025
- Primary completion27 Jul 2026
- Study completion27 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Block Complete HeartStudies 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
- Non-randomised
- Intervention model
- Crossover
- Model description
- Participants underwent two consecutive pacing periods, one with closed-loop stimulation (CLS) and one with accelerometer-based VVIR pacing. Seventeen participants started with CLS followed by VVIR, whereas 16 participants started with VVIR followed by CLS. The order of pacing modes was not randomized.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 33 participants (actual)
Sponsor and investigators
- Lead sponsor
- Bartlomiej Wrobel
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Bartlomiej Wrobel, University of Rzeszow
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07812935
- Sponsor's protocol ID
- 039/05/2025
- Status last verified
- Sep 2026
- First submitted
- 29 Aug 2026
- Last updated
- 10 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: There is currently no plan to make individual participant data publicly available.
Study at a glance
From the registry record, last updated by the sponsor on 10 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Closed-Loop Stimulation Combined With Left Bundle Branch Area Pacing in Patients With Atrioventricular Conduction Disorders
- ClinicalTrials.gov ID
- NCT07812935
- Acronym / sponsor ID
- 039/05/2025
- Keywords
- left bundle branch area pacing, closed loop stimulation, LBBAP, CLS, Rate adaptive pacing, cardiac pacing
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 33 participants (actual)
- Lead sponsor
- Bartlomiej WrobelUniversity, hospital or other
- Study start
- 23 Jun 2025 (actual)
- Primary completion
- 27 Jul 2026 (actual)
- Study completion
- 27 Jul 2026 (actual)
- First posted
- 10 Sep 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.
This prospective, single-center, crossover study evaluated the effects of closed-loop stimulation (CLS) compared with conventional accelerometer-based rate-adaptive pacing (VVIR) in patients with permanent atrial fibrillation undergoing left bundle branch area pacing (LBBAP). Chronotropic responses were evaluated during standardized mental and physical stress testing. Heart rate distribution during daily activity, functional capacity, quality of life, and device-related parameters were also assessed.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- Participants underwent two consecutive pacing periods, one with closed-loop stimulation (CLS) and one with accelerometer-based VVIR pacing. Seventeen participants started with CLS followed by VVIR, whereas 16 participants started with VVIR followed by CLS. The order of pacing modes was not randomized.
| Arm | Type | Receives |
|---|---|---|
| CLS followed by VVIR | Experimental | Device: Closed-Loop Stimulation, Device: Accelerometer-Based VVIR PacingParticipants received closed-loop stimulation (CLS) during the first study period, followed by accelerometer-based VVIR pacing during the second study period. |
| VVIR followed by CLS | Experimental | Device: Closed-Loop Stimulation, Device: Accelerometer-Based VVIR PacingParticipants received accelerometer-based VVIR pacing during the first study period, followed by closed-loop stimulation (CLS) during the second study period. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Age ≥18 years
- Permanent atrial fibrillation
- Chronotropic incompetence
- Permanent pacemaker with left bundle branch area pacing (LBBAP)
- Ventricular pacing burden >50%
Key exclusion criteria (2 listed)
- Age <18 years
- Inability or unwillingness to provide informed consent
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 |
|---|---|---|
| Closed-Loop StimulationThe pacemaker was programmed to closed-loop stimulation (CLS), an impedance-based rate-adaptive pacing algorithm that adjusts the pacing rate in response to changes in intracardiac impedance associated with cardiac contractile dynamics. | Device | CLS followed by VVIR, VVIR followed by CLS |
| Accelerometer-Based VVIR PacingThe pacemaker was programmed to VVIR mode with accelerometer-based rate-adaptive pacing. The pacing rate was adjusted according to physical activity detected by the device's accelerometer. | Device | CLS followed by VVIR, VVIR followed by CLS |
Primary outcome
Change in Heart Rate During Mental Stress
Time frame: At the end of each 1-month pacing period
Change in heart rate (ΔHR) during the Paced Auditory Serial Addition Test (PASAT), calculated as the peak heart rate recorded during the test minus the baseline heart rate. The outcome was assessed under both closed-loop stimulation (CLS) and accelerometer-based VVIR pacing and expressed in beats per minute (bpm).
Change in Heart Rate During Isometric Handgrip
Time frame: At the end of each 1-month pacing period
Change in heart rate (ΔHR) during the 5-minute isometric handgrip test performed at 30% of maximal voluntary contraction, calculated as the peak heart rate recorded during the test minus the baseline heart rate. The outcome was assessed under both closed-loop stimulation (CLS) and accelerometer-based VVIR pacing and expressed in beats per minute (bpm).
Change in Heart Rate During Treadmill Exercise
Time frame: At the end of each 1-month pacing period
Change in heart rate (ΔHR) during the symptom-limited treadmill exercise test using the modified Bruce protocol, calculated as the peak heart rate achieved during exercise minus the baseline heart rate. The outcome was assessed under both closed-loop stimulation (CLS) and accelerometer-based VVIR pacing and expressed in beats per minute (bpm).
7 secondary outcomes
Exercise Duration During Treadmill Testing
Time frame: At the end of each 1-month pacing period
Metabolic Equivalents Achieved During Treadmill Testing
Time frame: At the end of each 1-month pacing period
Heart Rate Score During Daily Activity
Time frame: At the end of each 1-month pacing period
Health-Related Quality of Life Assessed With the EQ-5D-5L Index
Time frame: At the end of each 1-month pacing period
Self-Rated Health Assessed With the EQ VAS
Time frame: At the end of each 1-month pacing period
Patient-Reported Pacing-Mode Preference
Time frame: At the end of the study, after completion of both 1-month pacing periods
Ventricular Pacing Percentage
Time frame: At the end of each 1-month pacing period
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Sep 2026.
- Individual participant dataSharing planned: No. There is currently no plan to make individual participant data publicly available.
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Closed-Loop Stimulation and Accelerometer-Based VVIR Pacing in people with Block Complete Heart and Atrial Fibrillation (AF), run by Bartlomiej Wrobel at 1 site in Poland.
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 2 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: finished, as of the sponsor's last update on 10 Sep 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 Poland. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Heart Rate During Mental Stress (time frame: At the end of each 1-month pacing period). 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 10 Sep 2026.