heart physiology

HR

heart rate

heart rate

number of beats per min (bpm)

SV

stroke volume

stroke volume

amount of blood the heart pumps in one beat (measured in mL or L)

CO

cardiac output

cardiac output

amount of blood the heart sends to the body in one min

CO = SV x HR

formula for calculating cardiac output (CO)

5 L/min

CO at rest

systole

heart contraction

diastole

heart relaxation

BP = CO x PVR

formula for blood pressure (assuming peripheral vascular resistance (PVR) is constant

venous return

amount of blood that comes back from the body to the heart

preload

amount of blood the heart receives (before sending it to the body)

afterload

force needed to pump blood (relies on blood pressure (BP))

EDV

end diastolic volume

end diastolic volume

amount of blood inside the heart at the end of the diastole period (relaxation); occurs before the systolic period

ESV

end systolic volume

end systolic volume

amount of blood that remains inside the heart at the end of the systolic period

ejection fraction

percent amount of blood pumped from the heart per contraction