10 Integrated Cardiac Pharmacology Flashcards
where is the ANS cardiac control center in the CNS?
rostral ventrolateral medulla(RVLM)
nucleus tractus solitarius(NTS)
what type of pressure are baroreceptors sensitive to?
pulse pressure
if the pulse pressure decreases, but mean pressure is the same, baroreceptor rate of discharge will still decrease
autonomic predominance in vasculature
sympathetic is the only innervation
vasoconstriction in arterioles and venules
cholinergic vasodilation in skeletal muscle arterioles
no PSYMP INNERVATION; M3 receptors in endothelium are not connected to nerves
stimulation of vagal c fibers arises from where?
effect?
atria, ventricles, great veins, pulmonary arteries, alveoli capillaries
bradycardia, hypotension, brief apnea- bezold-jarisch reflex
during exercise how is the sympathetic vasoconstriction of exercising muscle overcome to allow required perfusion
local vasodilators
stimulation of cholinergic vasodilatory fibers
dynamic whole body exercises affect the TPR how?
drop!
baroreceptors are not triggered
stages of valsalva maneuver
strain
- increased MAP, decreased HR(compensatory)
- decreased CO/MAP(less return), increased HR(compensatory)
release
- transient MAP decrease, CO is restored
- MAP ramp up w/compensatory drop in HR
cause of neurocardiogenic syncope
cardioinhibitory - increased PSYMP tone, bradycardia
vasodepressor - decreased sympathetic tone, hypotension
mixed - both HR and BP depressed
widely accepted theory: vagal afferents affect NTS to mediate these presentations
potential triggers for neurocardiogenic syncope
pain
visual stimuli
noxious stimuli
excessive standing(pooling)
exacerbation of neurocardiogenic syncope
treatment?
dehydrtation
anxiety
exogenous catecholamines
treatment: drink water, eat salt, shift weight while standing
tilt table test
- Pt lays horizontal and strapped down
- HR, ECG, BP recorded
- Table elevated to 70/80 deg
- Room darkened
- If no syncope after 20 min, isoproterenol is administered IV for 20 min(increase HR, decrease BP)
- Test considered negative if no event @ 40m