Ejection fraction (EF) is the percentage of blood the heart ejects from the left ventricle in one contraction. It is the key measure of the heart's pumping function, measured on ultrasound (echocardiography).
For example, an EF of 60% means that per beat the heart ejects 60% of the blood that filled the ventricle. EF largely determines the type and severity of heart failure — together with NT-proBNP.
Reference ranges
Left-ventricular ejection fraction (%):
| Normal | 55 – 70% |
| Mildly reduced | 41 – 49% (HFmrEF) |
| Markedly reduced | < 40% (HFrEF) |
| Preserved EF | ≥ 50% (HFpEF — failure with a normal EF) |
What an elevated level means
An ejection fraction above normal is uncommon and usually not a problem in itself. A very high EF is sometimes seen in hypertrophic cardiomyopathy or with a small ventricular volume — a cardiologist assesses this from the whole echocardiographic picture.
In most cases "the higher the EF the better" within the normal range — it is a fall that is the concern.
What a low level means
A reduced ejection fraction means the heart pumps blood weakly — this is systolic heart failure (HFrEF at an EF < 40%).
Causes: a past heart attack, long-standing hypertension, cardiomyopathies, valve disease and myocarditis. Symptoms are breathlessness, fatigue and edema. A reduced EF needs treatment by a cardiologist, which genuinely improves the outlook.
How the test is done
Ejection fraction is most often measured on echocardiography (a heart ultrasound), less often on cardiac MRI or nuclear methods. It is non-invasive and painless.
EF is interpreted together with symptoms, NT-proBNP and an assessment of diastolic function — because failure also occurs with a preserved EF (HFpEF).
What affects the value
- A past heart attack — lowers EF.
- Long-standing hypertension — lowers it over time.
- Cardiomyopathies and myocarditis — lower it.
- Valve disease — affects EF.
- Heart-failure treatment — may raise EF.
- The ultrasound method and operator — affect the accuracy of the estimate.
Estimate your heart age
Ejection fraction is the basis of heart assessment on echocardiography; find out your heart age:
Frequently asked questions
What ejection fraction is considered normal?
55–70%. Values of 41–49% mean mildly reduced function, below 40% marked systolic heart failure. At the same time, heart failure is possible with a normal EF (≥50%) if the heart relaxes poorly.
Can a reduced ejection fraction be raised?
Often yes. Modern heart-failure treatment (medicines and, if needed, devices) can improve the ejection fraction and, more importantly, the outlook and how you feel. A cardiologist decides on the approach.
I'm breathless but my EF is normal — is that possible?
Yes. This is heart failure with a preserved ejection fraction (HFpEF): the heart contracts normally but relaxes and fills poorly. So a normal EF does not rule out a cardiac cause of breathlessness — NT-proBNP and diastolic function are also assessed.
Related terms
Sources
- Ejection fraction and heart failure classification (review). NCBI/PMC
- American Heart Association — Ejection Fraction Measurement
- MedlinePlus (NIH) — Heart Failure