<prompt> A 25-year old athlete has an ejection fraction of 0.50 and an end-systolic volume of 50 mL. What is his end-diastolic volume?75 mL100 mL125 mL150 mL  <response>: Ejection fraction X 100 EDV - SV ESV end-systolic volume If ejection fraction is 0.5 or 50, it means 50 of the EDV is pumped out as stroke volume; and remaining 50 is left behind as end-systolic volume ESV. ESV given is 50 mL; so EDV would be 100 mL. 