<prompt> Answer this question truthfullyCould you explain the meaning of ejection fraction, please?  <response>: <reason> In cardiovascular physiology, ejection fraction E f is the fraction of blood pumped out of a ventricle with each heart beat. The term ejection fraction applies to both the right and left ventricles; one can speak equally of the left ventricular ejection fraction LVEF and the right ventricular ejection fraction RVEF. Without a qualifier, the term ejection fraction refers specifically to that of the left ventricle.By definition, the volume of blood within a ventricle immediately before a contraction is known as the end-diastolic volume. Similarly, the volume of blood left in a ventricle at the end of contraction is end-systolic volume. The difference between end-diastolic and end-systolic volumes is the stroke volume, the volume of blood ejected with each beat. Ejection fraction E f is the fraction of the end-diastolic volume that is ejected with each beat; that is, it is stroke volume SV divided by end-diastolic volume EDV:E_f fracSVEDV fracEDV - ESVEDV 