Hemodynamics
of
Large Arteries
113
-
p
60
-
r
E
40
-
g
20-
B
0-
8
-
-
c
-20
-
-40
vasoconstriction and vasodilation conditions. Vasoconstriction
is
induced
by intravenous infusion of methoxamine,
a
potent vasoconstrictor. Its
primary effect
is
in increasing peripheral vascular resistance and has little
cardiac effect.
Vasodilation in induced by intravenous infusion of
nitroprusside.
This
is
a common vasodilator that can profoundly
decrease peripheral vascular resistance and increase arterial compliance.
It can be seen that the pressure waveform during strong vasodilation
more closely resembles that of the flow waveform.
-
-
-
-
I
I
I
I
I
I
I
CONTROL
-pressure
115
110
105
m
I
v
g
100
g
95
I
‘d
90
0
.-
c
m
I
I
I
I
I
I
I
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
time
(sec)
CONTROL
-flow
loo
80
m
time (sec)
Fig.
4.4.2:
Ascending aortic pressure (top) and flow (bottom) waveforms resolved into
their respective forward (Ps Qf) or antegrade,
and
reflected
(P,,
Q,)
or retrograde
components. Notice that wave reflection
exerts
opposite effects on pressure and
flow
waveforms,
as
seen from
Qr
and P,.
Provided
by
Dr. Ying Zhu.
