What is Ejection Fraction?
Ejection fraction (EF) is the percentage of blood ejected from the ventricle during systolic contraction, calculated as: EF = ([EDV - ESV] / EDV) × 100, where EDV is end-diastolic volume and ESV is end-systolic volume 1.
How It's Calculated
EF can be determined through two primary methods:
- Visual estimation: A clinician's visual assessment of ventricular contraction on imaging, reported as a single value or midpoint of a range 1
- Calculated measurement: Using the formula above with measured ventricular volumes from echocardiography, cardiac MRI, or other imaging modalities 1
The calculation applies to both left ventricular ejection fraction (LVEF) and right ventricular ejection fraction (RVEF), though LVEF is far more commonly used clinically 1.
Normal Values
For healthy adults, the lower limit of normal LVEF is approximately 53% for women and 52% for men 2. The pooled mean LVEF across population studies is 62.8%, with normal range extending from approximately 52% to 73% 2.
Key demographic variations:
- Women have higher mean LVEF (63.7%) than men (61.9%), with corresponding lower normal limits of 52.7% and 51.7% respectively 2
- Age does not significantly affect normal LVEF values 2
- Individuals of Asian origin have 2-3 percentage points higher LVEF than Black or White individuals, with lower normal limits around 54% for women and 53% for men 2
An LVEF below 50% is highly unlikely to represent normal function (probability <5%) regardless of sex, age, or ethnicity 2.
Clinical Significance and Interpretation
Qualitative categories for left ventricular systolic function 1:
- Normal: Standard ventricular function
- Hyperdynamic: Greater than normal proportion of blood ejected (EF typically >70%)
- Mildly reduced: Slightly reduced ejection (typically EF 40-50%)
- Moderately reduced: Moderately impaired ejection (typically EF 30-40%)
- Severely reduced: Considerably reduced ejection (typically EF <30%)
Clinical applications:
EF serves as a cornerstone metric for:
- Heart failure classification: Distinguishing HFrEF (reduced EF, typically <40%) from HFpEF (preserved EF, >50%) 3
- Prognostic assessment: Strong predictor of adverse outcomes when below ~45% 4
- Treatment decisions: Guides medication choices, device therapy (ICD, CRT), and intervention timing 5
- Monitoring cardiotoxicity: Serial measurements in patients receiving chemotherapy 6
Important Limitations and Caveats
EF is both preload- and afterload-dependent, meaning it can change substantially based on loading conditions rather than true changes in contractility 4. This is a critical pitfall—a patient with severe mitral regurgitation may have a "normal" EF despite poor intrinsic myocardial function because the ventricle ejects into a low-resistance left atrium.
EF is less useful as a risk marker as it approaches normal values 4. A patient with an EF of 55% versus 65% may have clinically significant differences in ventricular function that EF alone cannot capture.
The relationship between EF and risk is modified by comorbidities including hypertension, diabetes, and renal function 4. Don't interpret EF in isolation from the clinical context.
Reproducibility is only moderate 4, and the area-based calculation method consistently underestimates EF compared to volume-based methods 7. Ensure consistency in measurement technique when following patients serially.
Beyond Ejection Fraction
While EF remains widely used, comprehensive cardiac assessment requires integration of additional parameters 4:
- Left and right ventricular function metrics (TAPSE, FAC, strain imaging)
- Left ventricular geometry and mass
- Left atrial volume (indexed to BSA)
- Valvular function
- Clinical parameters and biomarkers (natriuretic peptides)
Global longitudinal strain (GLS) detects subclinical LV dysfunction before EF declines, with normal values ranging from -18% to -22% 8. Consider incorporating strain imaging when available, particularly for early detection of cardiotoxicity or subtle dysfunction.
For right ventricular assessment, fractional area change (FAC), TAPSE, and RV free wall strain provide complementary information beyond RVEF alone 1, 8.