|
Philippe Gersbach, Ludwig K. von Segesser, Cardiovascular
Surgery, University Hospital Lausanne, Switzerland.
To determine whether SCS holds vasoactive properties that could
explain its alleged antianginal properties, broad invasive hemodynamic
testings were performed in 17 anesthetized Göttinger minipigs
at rest and under short- (10 minutes) and long-lasting (60 minutes)
high-cervical SCS at 2V, 5V and 10Volts.
Results: The following significant mean changes (p<0.05)
were elicited by SCS:
|
SCS
|
HR
|
MBP
|
CO
|
SV
|
SVR
|
PVR
|
|
2V
|
+ 14%
|
+ 9%
|
+ 34%
|
+ 19%
|
-17%
|
-25%
|
|
5V
|
+ 23%
|
+ 27%
|
+ 29%
|
+ 16%
|
ns
|
ns
|
|
10V
|
+ 14%
|
+ 40%
|
+ 28%
|
+ 15%
|
ns
|
ns
|
HR = heart rate, MBP= mean blood pressure,
CO = cardiac output, SV = stroke volume,
SVR/PVR = systemic/pulmonary vascular resistances.
The major increase in rate pressure product (RPP=SBPxHR) observed
during high-intensity SCS reflects a rise in cardiac work and
myocardial oxygen consumption that is out of proportion with the
increase in cardiac output. Conversely, under 2Volts SCS, the
RPP only moderately rises, while the cardiac output substantially
increases, indicating a particularly efficient and economical
cardiac work.
Conclusions: A diminution in peripheral resistances, cardiac
work and oxygen myocardial consumption may definitely improve
angina symptoms.
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