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Completed

NCT Number: NCT00508196

Endothelial Function and Cardiac Output in RV Pacing

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.

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Key information

Conditions

Bradycardia Arrhythmias, Cardiac Cardiovascular Diseases Heart Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms

Age range

21 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Ninewells Hospital and medical School

Dundee, DD1 9SY, United Kingdom

About this study

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.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Dual chamber pacemaker
  • Intact AV node function

Exclusion criteria

  • Unstable angina, heart failure
  • Inability to exercise

Treatment and study plan

RVP-min

Other

DDD pacing with long AV delay

Other names: DDD Long

RVP-max

Other

DDD pacing with short AV delay

Other names: DDD short

Primary outcomes

  1. Endothelial Function Assessed by Flow Mediated Vasodilatation

    Time frame: 1 week

    Flow mediated vasodilatation as measured by reactive hyperaemia peripheral arterial tonometry signal using EndoPAT software, Itamar.

    A post-occlusion to pre-occlusion ratio is calculated by the EndoPAT software, providing the EndoPAT index (EnFI)

Secondary outcomes

  1. B-type Natriuretic Pepetide

    Time frame: 1 week

  2. Cardiac Output

    Time frame: 1 week

    measured at peak exercise on a standard exercise bicycle, measured non-invasively using the inert gas rebreathing technique (Innocor, Innovision A/S, Odense, Denmark).

Sponsors and collaborators

Lead sponsor

University of Dundee

Other

Registry information

Official study title

Endothelial Function and Cardiac Output in Right Ventricular Pacing

Important dates

Study start
2006
Primary completion
2007
Study completion
2007
First posted
Jul 27, 2007
Registry last updated
Mar 18, 2019

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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