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Updated: Jul 7, 2026
Assessing Endothelial Vasodilator Function with the Endo-PAT 2000
Published on: October 15, 2010
The acute effect of cardiac pacing mode on endothelial vasodilation: prospective, double-blind, cross-over,
Ali Serdar Fak1, Beste Ozben, Ahmet Toprak
1Department of Cardiology, Marmara University Faculty of Medicine, Istanbul, Turkey. besteozben@yahoo.com
Insights
Ventricular demand pacing (VVI) impairs endothelial function, reducing flow-mediated dilation (FMD) compared to atrial-based pacing. This may contribute to negative hemodynamic effects in pacemaker patients.
Area of Science:
- Cardiology
- Vascular Biology
- Medical Devices
Background:
- Ventricular demand pacing (VVI) has known deleterious hemodynamic effects, potentially linked to sympathetic and baroreceptor activity.
- Endothelial function is sensitive to systemic and local factors, including baroreceptor influences.
Purpose of the Study:
- To investigate the impact of cardiac pacing modes on endothelial function.
- To compare endothelial function during atrial-based pacing versus ventricular demand pacing.
Main Methods:
- Twelve patients with pacemakers (DDD or VDD) were randomized to atrial-based or VVI pacing modes in a crossover design.
- Endothelial function was assessed using brachial artery ultrasonography, measuring flow-mediated dilation (FMD) and nitroglycerin-induced vasodilation.
Main Results:
- Ventricular demand pacing (VVI) significantly reduced flow-mediated dilation (FMD) compared to atrial-based pacing (P=0.015 for absolute, P=0.028 for percentage).
- No significant difference in endothelium-independent vasodilation (nitroglycerin-mediated) was observed between pacing modes.
Conclusions:
- Acute VVI pacing attenuates endothelial vasodilation (FMD) in patients with atrial-based pacing systems.
- Impaired endothelial vasodilation during VVI pacing may contribute to adverse hemodynamic and clinical outcomes.
Background:
Compared to atrioventricular sequential pacing, ventricular demand pacing is known to have somewhat more deleterious hemodynamic effects, which probably arise from increased sympathetic tonus and inappropriate baroreceptor activation. Endothelial function is affected by various local and systemic factors including baroreceptor activity. The aim of this study was to explore whether cardiac pacing would have any effect on endothelial functions.
Methods:
Twelve patients (six male, mean age: 75 +/- 9 years) with previously implanted DDD or VDDcardiac pacemakers were included. All patients had stable atrial rhythms during the study. Patients were randomized to either atrial-based pacing mode (VDD or DDD) or ventricular demand pacing mode (VVI) first, and then cross-over was performed with the other pacing mode. Endothelial function was assessed by brachial artery ultrasonography. Basal diameter of the brachial artery, and both flow-mediated dilation (FMD) and endothelium-independent vasodilation with nitroglycerin were measured 1 hour after each pacing mode.
Results:
Compared to atrial-based pacing mode, ventricular demand pacing was associated with a significantly worse FMD both as absolute and percentage values (0.17 +/- 0.09 mm vs 0.28 +/- 0.11 mm, P = 0.015 and 4.84 +/- 2.37 % vs 7.00 +/- 2.88 %, P = 0.028, respectively). However, there was no significant difference in nitroglycerin-mediated vasodilation values between the two pacing sessions.
Conclusions:
Acute ventricular demand pacing (VVI pacing) is clearly associated with attenuation of FMD in patients with atrial-based pacing systems. The attenuation of endothelial vasodilation might have a role in hemodynamic and clinical deterioration in patients with VVI pacemakers.
