Pressure volume loops Flashcards
What is the ejection fraction?
EF = SV / EDV.
The proportion of the blood that is in the heart at the end of diastole, which leaves during systole. = 63%
Draw a pressure volume loop for the left ventricle and label the valves, EDV, ESV and SV.
See notes.
How can SV be increased?
Increase EDV and/or decrease ESV.
How does exercise alter the loop?
Exercise requires an increase SV so must increase EDV and decrease ESV.
How can EDV be increased?
Increase the PRELOAD
What problem can reduce preload?
It is reduced by diastolic dysfunction
What is the effect of afterload on the loop?
Afterload increases ventricular pressure and ESV to reduce SV and the ejection fraction.
What is inotropy?
The strength of a contraction
How does an increase in inotropy affect the loop?
Increases SV and decreases ESV with no change in EDV.
