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A pumping heart generates a unidirectional blood flow in the
circulatory system while the cardiac valves open and close to prevent
reversal flow ensuring a unidirectional net flow. What if
the valves do not function normally?
If there is a unidirectional net flow
in a circulating system without valves, we call this phenomenon
valveless pumping (VP). There are examples of valveless
pumping in nature.
One is a unidirectional blood circulation in the human
embryo before the development of the heart valves. Another is a
thoracic pump mechanism during cardiopulmonary resuscitation (CPR).
Two controversial theories have been proposed to explain the
mechanism of blood flow during CPR: thoracic pump and cardiac pump.
The fundamental difference between these two mechanisms is whether the
mitral valve opens or closes during chest compression. In thoracic
pump models, the heart acts as a passive conduit for blood flow with
the mitral valve always open. Mathematical modeling of VP may explain how
blood flows without valves.
References
[1] Eunok Jung and Charles S. Peskin, Two-dimensional simulations of
valveless pumping using the immersed boundary method,
SIAM. J. Sci. Comput. Vol. 25, No. 6, pp. 2066-2083 (2004)
[2] E. Jung, S. Lim,W. Lee, and S. Lee, Computational models of valveless
pumping using the immersed boundary method
Comput. Methods Appl. Mech. Engrg. 197(25-28): 2329-2339 (2008)
[3] S. Lim and E. Jung, A three-dimensional model of a closed valveless
pump system immersed in a viscous fluid
SIAM J. Appl. Math. 70(6):1999-2022 (2010)
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