title: Arterial viscoelasticity: role in the dependency of pulse wave velocity on heart rate in conduit arteries.
abstract: Experimental investigations have established that the stiffness of large arteries has a dependency on acute heart rate (HR) changes. However, the possible underlying mechanisms inherent in this HR dependency have not been well established. This study aimed to explore a plausible viscoelastic mechanism by which HR exerts an influence on arterial stiffness. A multisegment transmission line model of the human arterial tree incorporating fractional viscoelastic components in each segment was used to investigate the effect of varying fractional order parameter (α) of viscoelasticity on the dependence of aortic arch to femoral artery pulse wave velocity (afPWV) on HR. HR was varied from 60 to 100 beats/min at a fixed mean flow of 100 ml/s. PWV was calculated by intersecting tangent method (afPWVTan) and by phase velocity from the transfer function (afPWVTF) in the time and frequency domain, respectively. PWV was significantly and positively associated with HR for α ≥ 0.6; for α = 0.6, 0.8, and 1, HR-dependent changes in afPWVTanwere 0.01 ± 0.02, 0.07 ± 0.04, and 0.22 ± 0.09 m/s per 5 beats/min; HR-dependent changes in afPWVTFwere 0.02 ± 0.01, 0.12 ± 0.00, and 0.34 ± 0.01 m/s per 5 beats/min, respectively. This crosses the range of previous physiological studies where the dependence of PWV on HR was found to be between 0.08 and 0.10 m/s per 5 beats/min. Therefore, viscoelasticity of the arterial wall could contribute to mechanisms through which large artery stiffness changes with changing HR. Physiological studies are required to confirm this mechanism.NEW & NOTEWORTHYThis study used a transmission line model to elucidate the role of arterial viscoelasticity in the dependency of pulse wave velocity on heart rate. The model uses fractional viscoelasticity concepts, which provided novel insights into arterial hemodynamics. This study also provides a means of assessing the clinical manifestation of the association of pulse wave velocity and heart rate.
authors.affiliation: Chongqing Key Laboratory of Modern Photoelectric Detection Technology and Instrument, Chongqing Key Laboratory of Fiber Optic Sensor and Photodetector, Chongqing University of Technology, Chongqing, China.|Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia; and.
authors.forename: Hanguang
authors.initials: H
authors.lastname: Xiao
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia; and.
authors.forename: Isabella
authors.initials: I
authors.lastname: Tan
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia; and.
authors.forename: Mark
authors.identifier: http://orcid.org/0000-0002-2746-4222
authors.initials: M
authors.lastname: Butlin
authors.affiliation: Sichuan Mianyang 404 Hospital, Mianyang, China.
authors.forename: Decai
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia; and alberto.avolio@mq.edu.au.
authors.forename: Alberto P
authors.initials: AP
authors.lastname: Avolio
mesh_terms: D000222:Adaptation, Physiological; D001013:Aorta, Thoracic / Q000033:anatomy & histology / Q000502:physiology*; D001783:Blood Flow Velocity; D004548:Elasticity; D005263:Femoral Artery / Q000033:anatomy & histology / Q000502:physiology*; D006339:Heart Rate; D006801:Humans; D008955:Models, Cardiovascular; D063177:Pulse Wave Analysis; D012039:Regional Blood Flow; D013997:Time Factors; D059289:Vascular Stiffness; D014783:Viscosity
keywords: arterial stiffness; heart rate; pulse wave velocity; transmission line model; viscoelasticity