Endothelial Function and Cardiac Output in RV Pacing

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00508196
Recruitment Status : Completed
First Posted : July 27, 2007
Last Update Posted : July 27, 2007
Information provided by:
University of Dundee

Brief Summary:
Pacing from the right ventricle (as is current practice in patients implanted with permanent pacemakers for bradycardia), has been associated with worse outcomes particularly in heart failure patients. Recent clinical trials suggest that chronic right ventricular pacing (VP) is associated with worsening heart failure, increased strokes and atrial fibrillation. Hemodynamically, right VP results in delayed activation and contraction of the LV which can give rise to functional mitral regurgitation, shortened diastolic filling time and thus reduced coronary filling, as well as abnormal arterial pulsatile flow. The mechanisms for the deleterious effects of right VP in heart failure patients have not been previously investigated. Our aim of this study is therefore to investigate the hemodynamic effects of right VP in stable heart failure patients in terms of exercise cardiac output (CO, an important measure of myocardial function and prognosis), as well as endothelial function which may be deranged as a result of abnormal arterial pulsatile flow.

Condition or disease Intervention/treatment Phase
Bradycardia Procedure: Dual chamber pacing with long AV delay Procedure: VVI pacing Not Applicable

Detailed Description:

Study Aims The aim of this study is to investigate the effect of right ventricular pacing on CO at rest and exercise, and on endothelial function and B-type natriuretic peptide, BNP, in patients with heart failure.

Methods: Thirty patients with dual chamber pacemakers for sinus node disease will be recruited: 15 controls with normal LV function and 15 with stable impaired LV function (ejection fraction <40%). The pacemaker will be programmed to pace to back-up pacing at 55bpm in the atrial only (AAI, no right VP) for one week (baseline); and than programmed to overdrive pacing at 70-80bpm, randomised to either to dual chamber, DDD (sequential atrial and ventricular pacing) with a short AV delay (to ensure maximal right VP) or AAI (no RV pacing), for 1 week. There will be a crossover after a 1 week washout at backup AAI pacing at 55 bpm. Resting and exercise CO will be measured at the end of each pacing mode intervention using the Inocor system (a validated non invasive method of CO measurement, using inhaled inert gas equilibriums). Endothelial function will be measured non-invasively at the same time points, as will plasma BNP, a measure of LV strain. Patients with unstable heart failure or angina will be excluded.

Study Endpoints: Rest and exercise CO; and endothelial function and BNP with and without RV pacing, in patients with preserved and impaired LV function.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 22 participants
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: Double
Primary Purpose: Treatment
Official Title: Endothelial Function and Cardiac Output in Right Ventricular Pacing
Study Start Date : November 2006
Actual Study Completion Date : July 2007

Arm Intervention/treatment
Experimental: A1
Dual chamber pacing with long AV delay
Procedure: Dual chamber pacing with long AV delay
for 1 week

Experimental: A2
Dual chamber pacing with long AV delay
Procedure: Dual chamber pacing with long AV delay
for 1 week

Experimental: A3
VVI pacing
Procedure: VVI pacing
30 min

Primary Outcome Measures :
  1. endothelial function and cardiac output [ Time Frame: 30min to 1 week ]

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Ages Eligible for Study:   21 Years to 85 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Dual chamber pacemaker
  • Intact AV node function

Exclusion Criteria:

  • Unstable angina, heart failure
  • Inability to exercise

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00508196

United Kingdom
Ninewells Hospital and medical School
Dundee, United Kingdom, DD1 9SY
Sponsors and Collaborators
University of Dundee
Study Director: Allan Struthers, MD University of Dundee Identifier: NCT00508196     History of Changes
Other Study ID Numbers: 190906ver3
First Posted: July 27, 2007    Key Record Dates
Last Update Posted: July 27, 2007
Last Verified: July 2007

Keywords provided by University of Dundee:
right ventricular pacing
endothelial function
cardiac output

Additional relevant MeSH terms:
Arrhythmias, Cardiac
Heart Diseases
Cardiovascular Diseases
Pathologic Processes