Resonance. The missing phenomenon in hemodynamics.

Abstract

To simulate a short segment of the aorta, we studied wave propagation in an elastic tube with a side branch balloon. The small balloon simulated the organ (group of arterioles). Ligation of this side branch would reduce the moduli of the higher harmonics when the length of the side branch was appropriate. Electrical analogy of vessels was used to analyze this phenomenon. This simulation can explain the ligation results we found in rats. It may also clarify the discrepancies between the prediction of the Womersley equation and the experimental results. We suggest that the aorta and the closely attached organ can produce coupled oscillation; theoretically, this structure is equivalent to a resonance circuit.

Power Spectral Analysis of Finger Plethysmographic Waveform in Patients With Coronary Artery Disease and After Coronary Artery Bypass Graft Surgery

“…This suggests that the aorta and closely related organs may cause coupled oscillation or resonance. 24,36 In the presents study, we found that CAD and CABG surgery could change not only TPp but also normalized the power of individual harmonics. Our findings suggest that cardiovascular disease might redistribute the energy in the cardiovascular system such that high-frequency oscillations are reduced while low-frequency oscillations are increased and in addition, an increase in TPp.…”

“…Our findings suggest that cardiovascular disease might redistribute the energy in the cardiovascular system such that high-frequency oscillations are reduced while low-frequency oscillations are increased and in addition, an increase in TPp. By using the resonance theory of Wang et al, 24 the changes in the power spectrum of the plethysmographic waveform observed in this study might be caused by changes in coupled oscillation, which was in turn caused by changes in the effective plasma flow to various organs supplied by the aorta. The pathological changes in the blood vessels because of CAD and CABG might play a role in changing the effective plasma flow.…”

“…19,21 It was found that the physical conditions of the organ systems are related to specific Fourier components of the blood pressure pulse via their influence on the blood pressure wave propagation, and thus the blood distribution within the body. [22][23][24] Therefore, power spectral analysis of the plethysmographic waveforms is a useful method with which to assess the human cardiovascular system. 12 The autonomic nervous system controls almost all body functions and activities and its actions may influence the pulse.…”

Pressure wave propagation in liquid-filled tubes of viscoelastic material

“…The effect of the coefficient of wave reflection at the tube end and the wall material parameters on the fluid volume flow-rate and the tube wall displacement is investigated. It is shown that the volume flow-rate phase spectrum characteristics depend only slightly on the wall properties and can be used in clinical diagnostics for finding the reflection coefficient from pressure and flow-rate records.Keywords: pulse wave, viscoelastic tube, wave reflection.The propagation of pressure waves in liquid-filled compliant tubes has been intensely investigated in connection with the analysis of pulse waves in arteries [1][2][3][4][5]. The arterial vessels are multilayer tubes of viscoelastic orthotropic material and blood is a concentrated suspension of aggregating particles; therefore taking into account the fluid and wall rheology leads to fairly cumbersome mathematical models [6,7] that can be investigated only numerically.…”

“…The propagation of pressure waves in liquid-filled compliant tubes has been intensely investigated in connection with the analysis of pulse waves in arteries [1][2][3][4][5]. The arterial vessels are multilayer tubes of viscoelastic orthotropic material and blood is a concentrated suspension of aggregating particles; therefore taking into account the fluid and wall rheology leads to fairly cumbersome mathematical models [6,7] that can be investigated only numerically.…”