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Wave Speed and Characteristic Impedance

  • Nicolaas Westerhof
  • Nikolaos Stergiopulos
  • Mark I. M. Noble
Chapter

Abstarct

Wave speed, c, and characteristic impedance, Z c , are two important vessel parameters determining its wave transmission and reflection properties. These two quantities can be derived from so-called wave transmission theory, in analogy to what happens in telegraph lines, or antenna cables, for the transmission of electromagnetic waves. The characteristic impedance Z c = √ Z l Z t ′, with Z l ′ and Z t ′ the longitudinal and transverse impedance per length as given in Appendix 3. For large vessels like the aorta (large Womersley’s α) is Z c = √ Z l Z t ′ = √ L′/C A = √ρΔPA·A,

Keywords

Reflection Coefficient Pulse Wave Velocity Wave Speed Input Impedance Wave Transmission 
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References

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    Westerhof BE, Guelen I, Westerhof N, Karemaker JM, Avolio A. Quantification of wave reflection in the human aorta from pressure alone: a proof of principle. Hypertension 2006;48:595–601.PubMedCrossRefGoogle Scholar

Copyright information

© Springer US 2010

Authors and Affiliations

  • Nicolaas Westerhof
    • 1
  • Nikolaos Stergiopulos
    • 2
  • Mark I. M. Noble
    • 3
  1. 1.Departments of Physiology and Pulmonology ICaR-VUVU University Medical CenterAmsterdamthe Netherlands
  2. 2.Laboratory of Hemodynamics and Cardiovascular TechnologySwiss Federal Institute of TechnologyLausanneSwitzerland
  3. 3.Cardiovascular MedicineAberdeen UniversityAberdeenScotland

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