Ejection Fraction is defined as which of the following?

Ejection Fraction is defined as which of the following?

• A. SV / CO × 100
• B. (EDV / ESV) × 100
• C. (SV / LVEDV) × 100; Normal 65-70%; decreases with heart failure, increases with contractility.
• D. SV / LVEDV × 50

Answer: (C)

Ejection fraction is the fraction of the left ventricular end-diastolic volume that is ejected with each heartbeat. It is calculated as the stroke volume divided by the left ventricular end-diastolic volume, multiplied by 100 to convert to a percentage. Since stroke volume equals EDV minus ESV, EF can also be written as (EDV − ESV) / EDV × 100. The normal range is about 65–70%. A decrease in EF indicates reduced systolic function, such as in heart failure, while EF can increase with improved contractility or positive inotropic states. The other formulas don’t measure this fraction of EDV ejected: for example, SV/CO relates to heart rate and output rather than the proportion ejected; EDV/ESV is just a volume ratio; and using a different scaling like SV/LVEDV × 50 isn’t the standard definition.

Ejection fraction is the fraction of the left ventricular end-diastolic volume that is ejected with each heartbeat. It is calculated as the stroke volume divided by the left ventricular end-diastolic volume, multiplied by 100 to convert to a percentage. Since stroke volume equals EDV minus ESV, EF can also be written as (EDV − ESV) / EDV × 100. The normal range is about 65–70%. A decrease in EF indicates reduced systolic function, such as in heart failure, while EF can increase with improved contractility or positive inotropic states. The other formulas don’t measure this fraction of EDV ejected: for example, SV/CO relates to heart rate and output rather than the proportion ejected; EDV/ESV is just a volume ratio; and using a different scaling like SV/LVEDV × 50 isn’t the standard definition.