Endothelial Function and Cardiac Output in RV Pacing

Bradycardia Clinical Trial

Official title:

Endothelial Function and Cardiac Output in Right Ventricular Pacing

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00508196
• Other study ID #: 190906ver3
• Status: Completed
• Phase: N/A
• Start date: November 2006
• Est. completion date: July 2007

Study information

• Verified date: March 2019
• Source: University of Dundee
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 22
• Est. completion date: July 2007
• Est. primary completion date: July 2007
• Accepts healthy volunteers: No
• Gender: All
• Age group: 21 Years to 85 Years

Eligibility

Inclusion Criteria:

• Dual chamber pacemaker

• Intact AV node function

Exclusion Criteria:

• Unstable angina, heart failure

• Inability to exercise

Related Conditions & MeSH terms

• Bradycardia

Intervention

Other:
• RVP-min
DDD pacing with long AV delay
• RVP-max
DDD pacing with short AV delay

Locations

Country	Name	City	State
United Kingdom	Ninewells Hospital and medical School	Dundee

Sponsors (1)

Lead Sponsor	Collaborator
University of Dundee

Country where clinical trial is conducted

United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Endothelial Function Assessed by Flow Mediated Vasodilatation	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)	1 week
Secondary	B-type Natriuretic Pepetide		1 week
Secondary	Cardiac Output	measured at peak exercise on a standard exercise bicycle, measured non-invasively using the inert gas rebreathing technique (Innocor, Innovision A/S, Odense, Denmark).	1 week