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NCT Number: NCT06601322

Functional Outcomes in CondUction System Pacing and Right Ventricular Synchrony (FOCUS-Right)

The goal of this prospective single center clinical trial is to evaluate the safety and feasibility of performing simultaneous exercise stress cardiac magnetic resonance (CPET-CMR) and cardiopulmonary exercise testing in patients with pre-existing left bundle branch area pacemakers (LBBAP) programmed to an atrial sensing mode. Measurements of right ventricular, left ventricular function, and exercise capacity will be obtained at various LBBAP programming parameters at rest and during low intensity exercise. The main aims of the study are:

* Demonstrate the safety and feasibility of performing CPET-CMR in patients with pre-existing LBBAP programmed to P-synchronous ventricular pacing mode. * Generate preliminary data evaluating differences in RV function, LV function, and exercise capacity during various pacemaker programming settings.

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Key information

Conditions

Left Branch Bundle Block Arrhythmias, Cardiac Bundle-Branch Block Cardiac Conduction System Disease Cardiovascular Diseases Heart Block Heart Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms RV - Right Ventricular Abnormality

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

About this study

Conduction system pacing, namely left bundle branch area pacing (LBBAP) represents an important pacing modality introduced to avoid the deleterious effects of non-physiologic ventricular activation during chronic right ventricular pacing and /or left bundle branch block (LBBBP). Previous studies have demonstrated that LBBAP exhibits similar or superior left ventricular resynchronization compared to conventional treatment modalities, the impact of this novel pacing strategy on the right ventricle has not yet been addressed. This study aims to demonstrate the safety and feasibility of assessing LBBAP performance with a focus on right ventricular function in a novel way utilizing Cardiopulmonary Exercise Testing and Exercise Stress Cardiac Magnetic Resonance.

The investigators plan a 1-day prospective non-randomized controlled pilot study in which up to 20 subjects with left bundle branch area pacemakers with evidence of output dependent anodal capture will undergo low intensity exercise CPET-CMR at three different LBBAP settings (underlying rhythm, non-selective left bundle pacing, non-selective left bundle pacing with anodal stimulation).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • presence of dual chamber LBBAP implantation
  • presence of anodal capture with bipolar pacing configuration as determined at pacing implant.

Exclusion criteria

  • Known history of chronotropic incompetence
  • high degree or complete heart block
  • inability to tolerate NVP during initial device interrogation
  • pregnancy
  • inability to undergo MRI or exercise utilizing supine bicycle at target work-load
  • presence of MRI unsafe pacemaker components.

Treatment and study plan

Pacemaker Interrogation and Electrocardiogram (ECG):

Other

Prior to the CMR study, subjects will undergo baseline interrogation of their dual chamber LBBAP to assess for appropriate device function. Lead capture characteristics will then be assessed with continuous intracardiac electrogram characteristics recorded from the atrial and ventricular lead with simultaneous 12-lead ECG rhythm strip recordings to assess for settings at which the investigators can differentiate aLBBAP, sLBBAP and nsLBBAP. Pacing output will be increased until left bundle branch area pacing with anodal capture is achieved, and then decreased until anodal capture is lost. These programming parameters will be recorded and utilized for Phase 2-3 of the CPET-CMR scan. 12-lead ECG rhythm strips of QRS morphology with each parameter set will be obtained and saved for later analysis.

Cardiopulmonary Exercise Test (CPET) and Exercise Stress Cardiac Magnetic Resonance (ExeCMR

Other

Following ECG and pacemaker analysis as above for safety, subjects will be fitted with 2 sets of MRI-compatible ECG monitoring systems a BP monitoring system , and a finger-tip pulse gating system. Imaging will be performed on a Magnetom Vida 3 Tesla scanner by trained CRM radiology technologists.

Continuous pacemaker telemetry (CPT)

Other

CPT will be established and supervised by a cardiac electrophysiologist to monitor for evidence of noise or artifact which may lead to inability to appropriately sense native atrial depolarization in DDD mode. Subjects with PM dependence are excluded. If noise is noted during scanning with NVP, then scanning will NOT be performed during P-synchronous pacing and will instead be performed during overdrive pacing at a rate above the patients maximal achieved heart rate with exertion during Phase 1. Thus, there is minimal risk to the subject from PM programming during CPET-CMR.

Primary outcomes

  1. Incidence of Pacemaker Atrial (P Wave) Over-Sensed Events

    Time frame: Day 1: From beginning of CPET-CMR imaging procedure to end of CPET-CMR imaging procedure on study day.

    Incidence of pacemaker atrial (P Wave) over sensing as derived from continuous pacemaker telemetry at optimal programmed atrial sensitivity.

Secondary outcomes

  1. Incidence of Pacemaker Atrial (P Wave) Under-Sensed Events

    Time frame: Day 1: From beginning of CPET-CMR imaging procedure to end of CPET-CMR imaging procedure on study day.

    Incidence of pacemaker atrial (P Wave) under sensing as derived from continuous pacemaker telemetry at optimal programmed atrial sensitivity.

  2. Left Ventricular Ejection Fraction (%)

    Time frame: Day 1: From beginning of CPET-CMR imaging procedure to end of CPET-CMR imaging procedure on study day.

    Left ventricular ejection fraction (%) as measured by cardiac magnetic resonance imaging.

  3. Right Ventricular Ejection Fraction (%)

    Time frame: Day 1: From beginning of CPET-CMR imaging procedure to end of CPET-CMR imaging procedure on study day.

    Right ventricular ejection fraction (%) as measured by cardiac magnetic resonance imaging.

Other outcomes

  1. Slope of VO2 as a Function of Work Rate

    Time frame: Day 1: From beginning of CPET-CMR imaging procedure to end of CPET-CMR imaging procedure on study day.

    Slope of VO2 as a function of work rate as quantified by cardiopulmonary exercise testing.

Study contacts

Contact information is provided by the study sponsor or research team.

Ajay Pillai

CONTACT

[email protected]

(478) 957-2109

Melissa Sears

CONTACT

[email protected]

804-828-1601

Sponsors and collaborators

Lead sponsor

Virginia Commonwealth University

Other

Registry information

Official study title

Functional Outcomes in CondUction System Pacing and Right Ventricular Synchrony The FOCUS-Right Pilot Study (FOCUS-Right)

Acronym: FOCUS-Right

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
Sep 19, 2024
Registry last updated
Jun 17, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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