Adaptive Cardiac Resynchronization Therapy in Patients With RBBB

Sponsor
Henry Ford Health System (Other)
Overall Status
Terminated
CT.gov ID
NCT05936294
Collaborator
Central Arkansas Veterans Healthcare System (U.S. Fed)
5
2
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42.5
2.5
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Study Details

Study Description

Brief Summary

This study will address whether acute adaptive RV pacing in sinus rhythm patients with severe LV systolic dysfunction and RBBB is superior to no ventricular pacing, and is as effective as echocardiographically optimized biventricular (BIV) pacing based on Medtronic ECG belt and cardiac performance as assessed by the echocardiographic parameters of RV and LV function.

Condition or Disease Intervention/Treatment Phase
  • Diagnostic Test: Optimization of CRT Device
N/A

Detailed Description

Current guidelines state that CRT implantation is less beneficial for patients with RBBB compared to those with LBBB (2). Current evidence suggests that frequent or persistent RV-only pacing in patients with narrow QRS and LV dysfunction can be harmful due to ventricular desynchronization attributable to RV apex pacing (3-5).

Studies suggest that LV-only pacing is not inferior to BIV pacing in sinus rhythm patients with LV dysfunction and LBBB and ICD back up (6,7). A novel algorithm of CRT by delivering synchronized LV pacing with the intrinsic conduction in patients with severe LV systolic dysfunction and LBBB (adaptive CRT) has been demonstrated to show that it is at least as effective as protocol-driven echocardiographic optimization. It also has shown a significant reduction in the probability of 30-day readmission for both HF and all-cause hospitalizations, 46% reduced incidence of AF compared to conventional CRT, and prolongation of CRT device battery life (8-10). Patients who had an adaptive CRT algorithm that provided > 50% synchronized LV pacing or had normal AV conduction with the adaptive CRT algorithm had decreased risk of death or heart failure hospitalization when compared to those with <50% synchronized LV pacing or echocardiography-optimized BIV pacing respectively (11). In another acute study the LV dP/dtmax was higher with LV than BIV pacing when LV pacing was associated with ventricular fusion caused by intrinsic activation (12).

Several studies have suggested that optimization of the programmed atrioventricular delay (AVD) and interventricular delay (VVD) delays may incrementally improve the long-term outcome of BIV pacing (13-15).

The lateral LV wall contracts early in patients with RBBB when compared to LBBB so LV pacing in the CRT devices is less likely to be beneficial. . In an experimental study of 12 dogs with tachycardia-induced cardiomyopathy and RBBB (6 dogs) or LBBB (6 dogs) (16), RV-only pacing enhanced LV function and synchrony as seen by dP/dtmax measured by catheter tip placed in the LV chamber and synchrony evaluation by cardiac MRI in the RBBB group as well or better than BIV pacing. LV-only pacing worsened function in the RBBB group.

RV-only pacing was also evaluated in a prospective study of 7 patients with RBBB and RV dysfunction with most patients having congenital heart disease. LV global function was intact at baseline (17). Sequential atrioventricular RV pacing with an atrioventricular delay of 90% of the PR interval was superior to atrial-only pacing for both improvement in RV dP/dtmax and LV cardiac index as seen at cardiac catheterization. The RV dP/dtmax increased by 22% in RBBB patients with RV pacing and QRS decreased from 163 +/- 39 to 126 +/- 31 ms. The two studies together suggest that most of the benefit from BIV pacing in patients with RBBB and HF is due to the RV pacing component and the benefit might be reduced due to the LV pacing component. Better timing of RV pacing in patients with RBBB might significantly decrease desynchronization from RV pacing and maximize the benefit of RV pacing as seen in adaptive LV-pacing CRT in patients with LBBB and LV systolic dysfunction.

These studies have led to the current hypothesis that adaptive RV pacing using RV-only pacing synchronized to LV activation when intrinsic AV conduction is normal is more physiological and will improve RV and LV function by Echocardiography parameters and on Medtronic ECG belt for activation in patients with RBBB and LV dysfunction because of improved synchronization and narrowing the QRS duration.

As a secondary goal, battery life with BIV pacing will be compared to adaptive RV pacing assuming at least 50% of RV-only pacing will be achieved with adaptive CRT for RBBB.

Study Design

Study Type:
Interventional
Actual Enrollment :
5 participants
Allocation:
N/A
Intervention Model:
Single Group Assignment
Masking:
None (Open Label)
Primary Purpose:
Diagnostic
Official Title:
Cardiac Resynchronization Therapy With Synchronized RV Pacing to Improve Cardiac Function in Patients With Right Bundle Branch Block and Systolic LV Dysfunction
Actual Study Start Date :
Sep 15, 2017
Actual Primary Completion Date :
Mar 31, 2021
Actual Study Completion Date :
Mar 31, 2021

Arms and Interventions

Arm Intervention/Treatment
Other: CRT Optimization

Each patient will have atrial pacing 10% higher than the sinus rate or atrial pacing at a rate of 60 bpm if significant sinus bradycardia is present. Each patient will have six ECGs and echocardiographic sequences performed in the same session. In addition six electrical activation evaluations by the Medtronic ECG belt will be done as well. The first study will always be with no ventricular pacing. One study will be echocardiography-optimized BIV pacing and four studies for echocardiography-optimized (?) adaptive RV-only pacing with different AV intervals. A random-sequence will be performed to determine the order for the rest of the studies.

Diagnostic Test: Optimization of CRT Device
Each patient will have atrial pacing 10% higher than the sinus rate or atrial pacing at a rate of 60 bpm if significant sinus bradycardia is present. Each patient will have six ECGs and echocardiographic sequences performed in the same session. In addition six electrical activation evaluations by the Medtronic ECG belt will be done as well. The first study will always be with no ventricular pacing. One study will be echocardiography-optimized BIV pacing and four studies for echocardiography-optimized (?) adaptive RV-only pacing with different AV intervals. A random-sequence will be performed to determine the order for the rest of the studies.

Outcome Measures

Primary Outcome Measures

  1. Effectiveness of adaptive Right Ventricular (RV) pacing [1 hour]

    Echocardiographic parameters to measure cardiac function, including: Left Ventricular Outflow Tract velocity time interval(LVOT VTI), dP/dt of Left Ventricle (LV) and RV, Myocardial Performance Index (MPI), Right Ventricular Outflow Tractvelocity time interval (RVOT VTI); and 3D derived Systolic Dyssynchrony Index (SDI).

Secondary Outcome Measures

  1. Battery/device longevity [1 hour]

    Calculations of current drain and pacing percentages for RV-only pacing versus BIV pacing. Measured by microjoule current consumption.

Eligibility Criteria

Criteria

Ages Eligible for Study:
18 Years to 89 Years
Sexes Eligible for Study:
All
Accepts Healthy Volunteers:
No
Inclusion Criteria: Included patients will have:
  • sinus rhythm or isolated atrial pacing

  • LV systolic dysfunction (EF <35% at time of device implant)

  • AV conduction <250 ms, RBBB, and

  • have an implanted CRT device based on the ACC/AHA/HRS guidelines (2, 18) or will have a CRT device implanted during the study enrollment per ACC/AHA/HRS guidelines (2).

Exclusion Criteria:
  • atrial fibrillation

  • atrial flutter

  • atrial tachycardia

  • AV delay > 250 ms

  • sinus tachycardia with resting heart rate at time of the study 100 bpm

  • frequent APCs (> 25% of the total beats/min) or PVCs (>20% of the total beats/min), or

  • patients with EF > 40% at time of enrollment (if LV systolic function was found to be improved from time of implant).

Contacts and Locations

Locations

Site City State Country Postal Code
1 Central Arkansas Veterans Healthare System Little Rock Arkansas United States 72205
2 Henry Ford Hospital Detroit Michigan United States 48202

Sponsors and Collaborators

  • Henry Ford Health System
  • Central Arkansas Veterans Healthcare System

Investigators

  • Principal Investigator: Waddah Maskoun, MD, Henry Ford

Study Documents (Full-Text)

None provided.

More Information

Publications

Responsible Party:
Dr. Waddah Maskoun, MD. Senior Staff Physician, Henry Ford Health System
ClinicalTrials.gov Identifier:
NCT05936294
Other Study ID Numbers:
  • E17154
First Posted:
Jul 7, 2023
Last Update Posted:
Jul 7, 2023
Last Verified:
Jun 1, 2023
Studies a U.S. FDA-regulated Drug Product:
No
Studies a U.S. FDA-regulated Device Product:
Yes
Product Manufactured in and Exported from the U.S.:
No
Additional relevant MeSH terms:

Study Results

No Results Posted as of Jul 7, 2023