Wave intensity analysis and the development of the reservoir-wave approach.
The parameters of wave intensity analysis are calculated from incremental changes in pressure and velocity. While it is clear that forward- and backward-traveling waves induce incremental changes in pressure, not all incremental changes in pressure are due to waves; changes in pressure may also be due to changes in the volume of a compliant structure. When the left ventricular ejects blood rapidly into the aorta, aortic pressure increases, in part, because of the increase in aortic volume: aortic inflow is momentarily greater than aortic outflow. Therefore, to properly quantify the effects of forward or backward waves on arterial pressure and velocity (flow), the component of the incremental change in arterial pressure that is due only to this increase in arterial volume--and not, fundamentally, due to waves--first must be excluded. This component is the pressure generated by the filling and emptying of the reservoir, Otto Frank's Windkessel.
Tyberg
John V
JV
Department of Cardiac Sciences, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada. jtyberg@ucalgary.ca
Davies
Justin E
JE
Wang
Zhibin
Z
Whitelaw
William A
WA
Flewitt
Jacqueline A
JA
Shrive
Nigel G
NG
Francis
Darryl P
DP
Hughes
Alun D
AD
Parker
Kim H
KH
Wang
Jiun-Jr
JJ
D001011:Aorta / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008955:Models, Cardiovascular; D011673:Pulsatile Flow / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology