Related Experiment Videos
Constructive and destructive addition of forward and reflected arterial pulse waves
C M Quick1, D S Berger, A Noordergraaf
1Center for Cerebrovascular Research, University of California, San Francisco, California 94110, USA. quickc@anestesia.ucsf.edu
Summary
This study introduces a novel, model-independent method to assess arterial pulse wave reflection effects on vascular input impedance, pulsatile pressure, and stroke work. The findings reveal reflection
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
- Hemodynamics
Background:
- Arterial pulse wave propagation and reflection physics are understood, but their impact on vascular input impedance (Z(in)), pulsatile pressure, and stroke work (SW) remains debated.
- Current methods to study reflection involve experimental abolition or model-dependent assumptions, limiting accurate assessment.
- A need exists for a direct, model-independent approach to evaluate reflection's influence on hemodynamic parameters.
Purpose of the Study:
- To develop and present a simple, model-independent method for directly evaluating the effect of arterial pulse wave reflection.
- To quantify the impact of reflection on vascular input impedance, pulsatile pressure, and stroke work using measured data.
- To analyze how reflection influences these parameters under varying physiological conditions, such as vasodilation and vasoconstriction.
Main Methods:
- Proposed a novel method utilizing measured pulsatile pressure (P) and flow (Q) to assess reflection effects.
- Leveraged the principle that characteristic impedance (Z(0)) represents Z(in) without reflection.
- Calculated pressure with reflection theoretically removed by multiplying flow (Q) with characteristic impedance (Z(0)).
Main Results:
- Demonstrated a method to directly evaluate the effect of reflection on hemodynamic parameters without experimental abolition or model assumptions.
- Found that reflection has minimal impact on pulsatile pressure and stroke work at normal pressures.
- Observed a greater effect of reflection during vasodilation and vasoconstriction, altering Z(in), P, and SW based on wave interference.
Conclusions:
- The developed method offers a direct and model-independent way to study arterial pulse wave reflection.
- Reflection's influence on vascular input impedance, pulsatile pressure, and stroke work is condition-dependent.
- Understanding reflection dynamics is crucial for accurate hemodynamic assessment, particularly in altered vascular states.