114
155
-
$
150
-
E
145
-
?
$
140
-
?
$
130
-
-
n,
-
,"
135-
._
-
125
I
I
I
I
Dynamics
of the
Vascular
System
-
-
-
-
-
-
MTX -pressure
160
I
I
I
I
I
200
I
I
I
I
I
I
150
a,
100
r
-
0
5
50
$0
$
.-
-50
-100
-150
I
I
I
I
I
I
-0.2
0.0
0.2
0.4
0.6
0.8
time (sec)
Fig.
4.4.3:
Ascending aortic pressure and flow waveforms resolved into their respective
forward and reflected components during vasoconstriction induced
by
intravenous
infusion of methoxamine. Notice the
significantly
increased
reflected
pressure
component.
Aortic pressure (top) and flow (bottom) waveforms resolved into their
respective
forward
(Pf, Qf)
or antegrade, and reflected
(P, Qr)
or
retrograde components are shown
in
Fig.
4.4.2.
It is clear that wave
reflection exerts opposite effects
on
pressure and flow waveforms. The
increased reflected pressure component adds to the forward wave to
result in the measured pressure waveform. Reflected wave has a more
significant effect in mid- to late systole to impede ventricular ejection.
Wave reflection decreases the flow, as the reflected component of flow is
mostly negative.
With an increased amount of wave reflection, the
