Cardiac PV Loops Flashcards
cardiac output
CO
total volume of blood pumping into the aorta and pulmonary artery in 1 minute
equation for CO
CO = SV x HR
is cardiac output in the RV >< or = LV
equal
stroke volume
amount of blood ejected with each beat
cardiac index
cardiac output indexed to body size
what are measures of cardiac performance
volume
pressure
flow (echocardiogram)
right vs left heart pressure
right: lower pressure system b/c PA is lower pressure than aorta
left: higher pressure system b/c aorta is higher pressure than PA
pressure volume loops
shows the relationship between pressure and volume during 1 cardiac cycle
PV Loop: marker A
end-systolic volume; volume remaining after contraction
AV: open (begins filling)
SL: closed
PV Loop: marker B
end-diastolic volume; volume in ventricles after filling
AV: close (allows pressure to rise)
SL: closed
PV Loop: marker C
pressure generated in ventricle prior to contraction
AV: closed
SL: opens –> ejection of blood
PV Loop: marker D
pressure remaining after emptying ventricle
AV: closed
SL: close –> prevent regurg
diastole on PV loop
ventricular relaxation and filling
A (early) –> B (late)
volume INCREASES
pressure NO CHANGE
low pressure phase allows for passive filling (atrial > ventricular contraction)
what is compliance
stretch of the ventricle walls that allows for minimal change in pressure during filling
isovolumetric contraction on PV loop
closing of AV valves
B (EDV) –> C
volume NO CHANGE
pressure INCREASES
moderate pressure phase - ventricular pressure rises until it exceeds aortic pressure
systole on PV loop
ventricular contraction nad ejection
C –> D
volume DECREASES
pressure INCREASES
high pressure phase (ventricular > aortic to allow for blood flow out of ventricles, then ventricular decreases until < aortic)
isovolumetric relaxation on PV loop
closing of SL valves
D (ESV) –> A
volume NO CHANGE
pressure DECREASES
