Hemodynamics
of
Large
Arteries
115
75
-
I"
70-
E
E
'
65-
F
+
60
-
v
2
Q
0
55
pressure amplitude is increased.
This is seen in the case of strong
vasoconstriction shown in Fig.
4.4.3.
Here reflected waves arrive earlier
and with greater magnitudes.
As
a consequence, the pulse pressure
is
significantly increased with a concurrent decrease in flow amplitude.
The time that takes for forward pressure to reach its peak is not too
different from that
of the reflected component.
With profound
vasodilation (Fig.
4.4.4),
the measured pressure and flow waveforms
resemble each other and both peak at about the same time. The reflected
wave is largely abolished. Thus, both pressure and flow waves are
transmitted with maximal efficiency.
I
I
I
I
I
I
I
I
I
I
NTP
-flow
120
1
I
I
I
I
I
I
100
4
-20
OL-
-0.2
-
-
-
-
-
-
I
I
I
I
I
-0.1
0.0
0.1
0.2
0.3
0.4
time
(sec)
Fig.
4.4.4:
Ascending aortic pressure and flow waveforms resolved into their respective
forward and reflected components during vasodilation induced by intravenous infusion of
nitroprusside. Notice the similarity between the pressure and flow waveforms and that
the reflected components
are
small.
