End-systolic volume refers to which of the following?

• A. The volume remaining in the ventricle after contraction
• B. The volume ejected per beat
• C. The volume ejected before contraction
• D. The volume in the ventricle at end of diastole

Answer: (A)

End-systolic volume is the amount of blood left in the ventricle after it has finished contracting. After the ventricle ejects blood during systole, the remaining blood in the chamber represents the end-systolic volume. This volume, together with the end-diastolic volume (the amount in the ventricle at end of diastole), determines stroke volume (SV = EDV − ESV) and gives insight into systolic performance. The volume ejected per beat is the stroke volume, not the end-systolic volume; the volume ejected before contraction isn’t a standard measurement; and the volume at end of diastole is the end-diastolic volume, not end-systolic. Therefore, the volume remaining after contraction best describes end-systolic volume.