Cardiac Dynamics
end-diastolic volume (EDV)
ejection fraction
stroke volume (SV)
end-systolic volume (ESV)
cardiac output (CO)
the amount of blood in the ventricle at the end of ventricular diastole (refilling)
the amount of blood ejected from the ventricle during a single beat
stroke volume x heart rate
the amount of blood in the ventricle at the end of ventricular systole (contraction)
EDV (before) - ESV (after) = SV
volume of blood the heart pumps out in a minute
the percentage of the EDV represented by the stroke volume
a measure of the hearts efficiency
SV / EDV
factors that affect ESV
contractility
afterload (amount of tension the ventricle must produce to force open the semilunar valve and eject blood)
pre-load (how much was put in)
hormones
ANS innervation
ex: aortic valve stenosis will result in increased afterload
factors that affect EDV
venous return
filling time (depends on HR)
it changes in response to alterations in: cardiac output, blood volume, peripheral circulation, and skeletal muscle activity
rate of blood flow over this period
ex: when you exercise you have more venous return
cardiac cycle
(2) atrial systole (contraction) ends and atrial diastole (relaxation) begins
(3) ventricular systole
(1) atrial systole (contraction) begins
(4) ventricular diastole
AV close, iso-volumetric
semilunar valves open, blood is ejected
all chambers relax
semilunar valves close