Ejection fraction
Read Your Scan Editorial Team·Last updated
Written from published radiology references and reviewed for plain language. Not written or signed by a physician, and not a diagnosis. How we write these pages →
In plain language
The percentage of the blood in a heart chamber that gets pumped out with each beat. It is a measurement of pumping efficiency, and a normal heart does not empty completely — which is why a healthy figure is nowhere near 100%.
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Where you'll see this
Echocardiogram and cardiac MRI reports; occasionally estimated on a CT.
Your report may word it “EF”, “LVEF” or “Left ventricular ejection fraction”. These mean the same thing.
Questions worth asking your doctor
- What category did I get, and what does that category normally lead to?
- What is the recommended next step for this category — waiting, another scan, or a biopsy?
- Who decides the timing, and what should I do if my symptoms change before then?
How often does this turn up?
Ejection fraction is reported on essentially every echocardiogram and cardiac MRI, and it is the single number most people take away from a heart scan. It is the proportion of the blood sitting in a chamber at the end of filling that is pushed out with the next beat, given as a percentage and almost always about the left ventricle, the chamber that supplies the body.
Does it mean something is wrong?
The number that surprises people is the normal one: a healthy left ventricle typically ejects somewhere around 55% to 70%, so a heart working perfectly well does not empty anywhere near completely. Below the normal range, the figure is grouped rather than read to the decimal, because the measurement itself carries a margin of error — two operators measuring the same heart can differ by several points, and the trend across scans is more informative than any single reading. A figure below normal describes reduced pumping efficiency; how much that matters depends on the cause, on your symptoms, and on what the rest of the study showed.
What to do with it
A normal figure usually needs nothing beyond whatever prompted the scan. A reduced one leads to working out why, since the treatment follows the cause rather than the number: heart failure of various kinds, valve problems, previous heart attacks, rhythm disturbances and some medications all affect it. Modern treatment can genuinely improve a reduced ejection fraction, which is why the figure is usually rechecked after a period on treatment rather than treated as fixed.
Frequently asked questions
- What is a normal ejection fraction?
- Broadly 55% to 70% for the left ventricle, though laboratories differ slightly on where they draw the line. A normal heart never approaches 100% — a substantial volume always remains in the chamber after each beat, and that is how it is designed to work.
- Is a low ejection fraction the same as heart failure?
- Not the same thing, though they are related. Heart failure is a clinical diagnosis based on symptoms and examination as well as measurements, and it can occur with a normal ejection fraction when the problem is with filling rather than pumping. The number is one input, not the diagnosis.
- Why did my ejection fraction change between scans?
- Partly real change and partly measurement variation. The technique carries an inherent margin, so a few percentage points between studies — especially between different methods or different operators — may mean nothing. Doctors read the direction of travel across several measurements rather than reacting to one.
Standard scoring systems
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