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Preload, afterload and contractility each deform this loop in a different direction. Drag them and the confusion between the three tends not to survive.
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Stroke volume
77 mL
Ejection fraction
64%
End-diastolic
120 mL
End-systolic
43 mL
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Try these
Ejection fraction around 60 percent.
Preload
Moves the right edge of the loop. More filling widens it and stroke volume rises, which is the Frank-Starling relationship drawn out.
Afterload
Raises the top of the loop. The ventricle opens against more pressure, cannot empty as far, so end-systolic volume rises and stroke volume falls.
Contractility
Rotates the end-systolic line. A steeper line means the ventricle empties to a smaller volume at the same afterload, so ejection fraction rises.
A teaching model, drawn from the standard elastance relationships. Real loops carry valve dynamics and wave reflection this does not attempt. How this content is written.