hemodynamics (heximer) Flashcards
what determines pressure generation in heart (laplace)
stress (force/area)*thickness of wall/radius
what are 2 main diffs between R and L vents.
L has smaller r and thicker walls
what factors does heart try to keep fixed
wall pressure
what happens @ beginning of systole
AV valve closes
what occurs after AV closes
isovolumic contraction
what ends isovolumic contraction
aortic valve opens
what ends isovolumic relaxation
AV valve closes
what does a PV loop measure
LV volume vs. pressure
what is ESV and where on loop
end systolic vol - least V, most P
what is EDV and where on loop
end distolic vol. - least P, most V
when does mitral valve open
low P, low, V
when does filling occur
between mitral opening and closing (EDV)
what is stroke vol calculation
EDV-ESV
what changes P-V loops
pre and pos load
what is ESPVR a measure of
heart function (contractility)
what is EDPVR a measure of
diastolic heart compliance
how to calculate CO
stroke vol * HR
what are 2 types of factors to influence CO
- intrinsic - hemodynamics
2. extrinisic - autonomic
how much can CO be changed by intrinsic during excercise
5-15L/min
based on starling, what will change CO
venous return (EDV)
what controls vent. filling (2)
venous pressure
vent compliance
6 factors affecting P veins
- blood volume
- vein compliance - symp.
- muscle activity
- venous contraction with valves
- neg thoroacic pressure
- gravity
how can ESV affect CO
- lower ESV - more forceful contraction
what determines ESV
- afterload (aortic pressure)
2. contraction strength
what P-V loop with be seen with aortic stenosis
tall thin loop to the R
what does direction of ESPVR indicate
left - stronger, R- weaker
