Pacing Affects Cardiovascular Endpoints in Patients With Right Bundle-Branch Block (The PACE-RBBB Trial)

This study has been completed.
American Heart Association
Information provided by (Responsible Party):
Duke University Identifier:
First received: July 22, 2010
Last updated: August 19, 2014
Last verified: August 2014

Heart failure (HF) affects 5 million Americans and is responsible for more health-care expenditure than any other medical diagnosis. Approximately half of all HF patients have electrocardiographic prolongation of the QRS interval and ventricular dyssynchrony, a perturbation of the normal pattern of ventricular contraction that reduces the efficiency of ventricular work. Ventricular dyssynchrony is directly responsible for worsening HF symptomatology in this subset of patients. Resynchronization of ventricular contraction is usually achieved through simultaneous pacing of the left and right ventricles using a biventricular (BiV) pacemaker or implantable cardioverter-defibrillator. Clinical trial evidence supporting the use of BiV pacing in patients with prolonged QRS duration was obtained almost exclusively in patients with a left bundle-branch block (LBBB) electrocardiographic pattern. Recent evidence suggests that resynchronization of ventricular contraction in patients with LBBB can be obtained by univentricular left ventricular pacing with equal or superior clinical benefits compared to BiV pacing. Animal studies suggest that ventricular resynchronization can be obtained in subjects with right bundle-branch block (RBBB) through univentricular right ventricular pacing. No clinical trial evidence exists to support the use of BiV pacing in patients with RBBB. Thousands of patients with symptomatic HF and RBBB currently have univentricular ICDs in place for the prevention of sudden cardiac death. Most of these devices are currently programmed to avoid RV pacing. We aim to determine if ventricular resynchronization delivered through univentricular RV pacing improves symptoms in patients with RBBB and moderate to severe HF who have previously undergone BiV ICD implantation for symptomatic heart failure. We further aim to determine if ventricular resynchronization improves myocardial performance and ventricular geometry as detected by echocardiographic measures and quality of life for patients with HF and RBBB. We hypothesize that RV univentricular pacing delivered with an atrio-ventricular interval that maximizes ventricular synchrony is equivalent to BiV pacing for improvement in cardiac performance, HF symptoms, and positive ventricular remodeling in patients with HF and RBBB.

Condition Intervention
Heart Failure
Right Bundle-Branch Block
Device: VVI-40
Device: RV DDD-40
Device: BiV DDD-40

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Pacing Affects Cardiovascular Endpoints in Patients With Right Bundle-Branch Block (The PACE-RBBB Trial)

Resource links provided by NLM:

Further study details as provided by Duke University:

Primary Outcome Measures:
  • The primary endpoint of the trial will be a comparison of the proportion of patients in each of the three treatment groups who demonstrate positive LV remodeling, defined as a decrease in LV end systolic diameter of >5mm. [ Time Frame: 6 months ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Secondary echocardiographic endpoints [ Time Frame: 6 months ] [ Designated as safety issue: Yes ]
    Comparisons of the derived velocity-time integral calculated on the aortic continuous wave Doppler-spectrogram, comparisons of LV and RV end-diastolic size, LV and RV EF, mitral and tricuspid regurgitation severity, and estimated RV systolic pressure.

  • Secondary endpoints of the PACE-RBBB trial will also include comparisons of NYHA functional class, 6-minute walk distance, and Minnesota quality of life questionnaire scores between treatment groups. [ Time Frame: 6 months ] [ Designated as safety issue: Yes ]
  • Arrhythmic events [ Time Frame: 6 months ] [ Designated as safety issue: Yes ]
    To determine if pacing mode impacts the frequency of ventricular arrhythmias, the incidence of ventricular tachyarrhythmia episodes on device interrogation will be compared between treatment group assignments. An episode will be considered ventricular arrhythmia if it lasts longer than 30 seconds or requires anti-tachycardia pacing or high voltage device therapy for termination.

Enrollment: 16
Study Start Date: January 2011
Study Completion Date: August 2014
Primary Completion Date: August 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: VVI-40
The placebo arm will be programmed to VVI (inhibited) mode at a lower rate of 40.
Device: VVI-40
Pacing mode set to VVI-40, RV only pacing
Experimental: RV DDD-40
RV DDD-40 will have an AV interval set to produce QRS fusion with the native conduction down the native left bundle
Device: RV DDD-40
ICD programmed to DDD-40, RV only pacing with aan AV interval producing QRS fusion on surface EKG.
Experimental: Bi-V DDD-40
Permits direct comparison of RV univentricular pacing and current standard of care (BiV) pacing.
Device: BiV DDD-40
ICD programmed to BiV pacing at a lower rate of 40


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Cardiomyopathy of either idiopathic or ischemic etiology
  • NYHA class III, or IV symptoms
  • Sinus rhythm
  • QRS complex duration > 130 msec in ≥ 2 surface ECG leads with RBBB
  • PR interval > 150 msec and < 240 msec
  • Prior implantation of dual chamber BiV ICD with apical RV lead location

Exclusion Criteria:

  • Myocardial infarction, major surgical procedure, or acute cardiac failure crisis requiring inotropes within 6 months of entry into the study
  • Atrial fibrillation or flutter lasting >12 hours within the last 6 months
  • Sick sinus syndrome, complete heart block, or other arrhythmias requiring pacemaker support
  • Pregnancy
  • Any other known condition other than heart failure that could limit exercise time or survival to < 6 months
  Contacts and Locations
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Please refer to this study by its identifier: NCT01169493

United States, North Carolina
Duke University Medical Center
Durham, North Carolina, United States, 27710
Durham VA Medical Center
Durham, North Carolina, United States, 27710
Sponsors and Collaborators
Duke University
American Heart Association
Principal Investigator: Brett D Atwater, MD Duke University
  More Information

No publications provided

Responsible Party: Duke University Identifier: NCT01169493     History of Changes
Other Study ID Numbers: Pro00025144, 10CRP3630033
Study First Received: July 22, 2010
Last Updated: August 19, 2014
Health Authority: United States: Institutional Review Board

Keywords provided by Duke University:
Heart Failure
Right Bundle-Branch Block
Cardiac Resynchronization Therapy

Additional relevant MeSH terms:
Bundle-Branch Block
Heart Block
Heart Failure
Arrhythmias, Cardiac
Cardiovascular Diseases
Heart Diseases
Pathologic Processes processed this record on August 31, 2015