Ejection fraction is defined as which ratio?

Ejection fraction is defined as which ratio?

• A. End-Diastolic Volume over Stroke Volume
• B. Stroke Volume divided by End-Diastolic Volume
• C. SV/EDV
• D. Cardiac Output divided by End-Diastolic Volume

Answer: (C)

The key idea is that ejection fraction measures what portion of the ventricle’s filling volume is pumped out with each beat. It is defined as stroke volume divided by end-diastolic volume, so EF = SV/EDV. Since SV = EDV − ESV, EF can also be written as (EDV − ESV)/EDV = 1 − (ESV/EDV). When expressed as a percentage, EF% = (SV/EDV) × 100%. A normal range is about 55–70%. This value reflects systolic function: a reduced EF indicates impaired pumping ability, while a normal or high EF can occur with preserved systolic function or hyperdynamic states.

The key idea is that ejection fraction measures what portion of the ventricle’s filling volume is pumped out with each beat. It is defined as stroke volume divided by end-diastolic volume, so EF = SV/EDV. Since SV = EDV − ESV, EF can also be written as (EDV − ESV)/EDV = 1 − (ESV/EDV). When expressed as a percentage, EF% = (SV/EDV) × 100%. A normal range is about 55–70%. This value reflects systolic function: a reduced EF indicates impaired pumping ability, while a normal or high EF can occur with preserved systolic function or hyperdynamic states.