title: Heart rate affects endothelial function in essential hypertension.
abstract: Increased heart rate (HR) is a risk factor for cardiovascular morbidity and mortality in the general population and in some clinical conditions. Endothelial dysfunction is an adverse prognostic factor for cardiovascular events. The aim of the study was to evaluate the effect of HR on central hemodynamic parameters and endothelial function in hypertension. We evaluated forearm blood flow (FBF) response to intra-arterial infusion of acetylcholine (ACh) and sodium nitroprusside (SNP) in 30 patients with HR ≤60 min(-1) and 30 with HR ≥80 min(-1). The FBF was measured by strain-gauge plethysmography. Transesophageal atrial pacing was used to increase the HR. Radial artery applanation tonometry and pulse wave analysis were used to derive central aortic pressures and correlate hemodynamic indices. The FBF response to ACh is lower in hypertensives with HR ≤60 min(-1) than in those with HR ≥80 min(-1) (10.6 ± 4.2 vs. 13.6 ± 5.1 ml × 100 ml(-1) of tissue × min(-1), P < 0.001). Vascular resistance decreases to 9.3 ± 2.8 U in patients with lower HR versus 7.2 ± 2.1 U in those with higher HR (P = 0.002). The FBF response to SNP is similar in both groups. Central systolic and pulse pressure are higher in bradycardic patients than in those with HR ≥80 min(-1) (140 ± 8 vs. 131 ± 8 mmHg, P = 0.0001 and 49 ± 10 vs. 39 ± 11 mmHg, P = 0.0001). All central hemodynamic parameters decrease during incremental atrial pacing. Augmentation index is the strongest predictor of endothelial dysfunction at multivariate analysis. These findings demonstrate that low HR affects endothelium-dependent vasodilation in hypertension. Increased central aortic pressure and hemodynamic correlates seem to be the underlying mechanisms by which bradycardia interferes with endothelium-dependent reactivity.
authors.affiliation: Department of Experimental and Clinical Medicine G. Salvatore, University Magna Græcia of Catanzaro, Catanzaro, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Maio
authors.forename: Sofia
authors.initials: S
authors.lastname: Miceli
authors.forename: Angela
authors.initials: A
authors.lastname: Sciacqua
authors.forename: Giulia Galiano
authors.initials: GG
authors.lastname: Leone
authors.forename: Rosamaria
authors.initials: R
authors.lastname: Bruni
authors.forename: Paola
authors.initials: P
authors.lastname: Naccarato
authors.forename: Francesco
authors.initials: F
authors.lastname: Martino
authors.forename: Giorgio
authors.initials: G
authors.lastname: Sesti
authors.forename: Francesco
authors.initials: F
authors.lastname: Perticone
mesh_terms: D000109:Acetylcholine; D000328:Adult; D002304:Cardiac Pacing, Artificial; D015331:Cohort Studies; D004730:Endothelium, Vascular / Q000503:physiopathology*; D000075222:Essential Hypertension; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009599:Nitroprusside; D010991:Plethysmography; D014664:Vasodilation / Q000502:physiology*; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D009599:Nitroprusside; D000109:Acetylcholine