If you need ejection fraction and stroke volume and you already have cardiac output, end diastolic volume (edv), end systolic volume (esv) and heart rate, this calculator does the substitution for you. It suits a quick check, a homework answer you want to confirm, or any figure you need to sanity test.
What Is the Ejection Fraction Calculator?
The ejection fraction calculator gives you an estimate of ejection fraction and stroke volume based on cardiac output, end diastolic volume (edv), end systolic volume (esv) and heart rate.
It is a quick reference figure rather than a diagnosis, and it is most useful for tracking how a number moves over time rather than for interpreting a single reading.
How the Ejection Fraction Estimate Is Worked Out
The calculation follows published reference relationships, so it is a reasonable approximation when the inputs are accurate. It assumes an average adult and does not account for individual variation.
If you are comparing two people, or the same person over a period of weeks, keep the method and the inputs identical. A change in the method can easily look like a change in the person.
What This Calculator Does Not Do
It does not diagnose anything, and it does not replace advice from a clinician. If a figure comes out at an extreme, or if it differs sharply from what you expect, that is a reason to speak to a professional rather than to adjust the inputs.
Nothing you type here is stored or sent anywhere. The whole calculation happens in your browser.
A Worked Example
Working through an example, with cardiac output set to 10, end diastolic volume (edv) set to 5, end systolic volume (esv) set to 2, the calculator returns stroke volume of 3, and ejection fraction of 0.6. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out ejection fraction?
Enter cardiac output, end diastolic volume (edv), end systolic volume (esv) and heart rate. The calculator then works through the relationship and reports ejection fraction and stroke volume.
What does the ejection fraction actually calculate?
It takes cardiac output, end diastolic volume (edv), end systolic volume (esv) and heart rate and converts them into ejection fraction and stroke volume using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter cardiac output?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Why does a small change in one value move the answer so much?
That happens when an output depends on a ratio, because dividing by a small number magnifies any change in it. Check the units first, then check whether the value you entered is in the range the relationship was designed for.
Do I have to fill in every field?
Only the fields a particular result depends on. If you leave one blank, the results that need it simply show a note instead of a number, and everything else still works.