Ejection Fraction
The percentage of blood in the left ventricle that is pumped out with each heartbeat. Central measurement of systolic cardiac function.
Ejection fraction is calculated as the stroke volume divided by the end-diastolic volume, expressed as a percentage. A normal LVEF in adults is typically 53–73% (ASE 2015 chamber-quantification guidelines).
EF is the single most-cited number in cardiac imaging. It drives heart-failure phenotyping (HFrEF ≤40%, HFmrEF 41–49%, HFpEF ≥50%), candidacy for device therapy (ICD / CRT), and post-MI risk stratification.
Manual EF measurement on echocardiography has well-documented inter-observer variability of 10–15%, a clinically meaningful range that AI-assisted measurement reduces by automating tracing on every loop.