Managing heart failure can also mean learning more about how your heart works and the words doctors use to describe its function. One term you may hear is your heart’s ejection fraction, a number that tells you and your doctor how well your heart is pumping blood.

“My doctor told me that I have a low ejection fraction. What does this mean and what can I do about it?” asked one member of MyHeartDiseaseTeam.

This article explains what ejection fraction is, what different ranges mean, and why it’s helpful to track it. It also explains how some treatments may help improve and protect heart function.

🗳️ Have you talked with a healthcare provider about what your ejection fraction means for your heart failure?

Yes, and it was helpful

Yes, but it wasn’t helpful

No, but I plan to

No, and I don’t plan to

Thanks! You've successfully submitted your vote.

Sign up to view the results!

Continue with Facebook

Continue with Google

Continue with Email

By joining, you accept our Terms of Use, and acknowledge our collection, sharing, and use of your data in accordance with our Health Data and Privacy policies.

Already a member? Log In

What Is Ejection Fraction?

When the heart contracts, blood is pumped out of the heart’s two lower chambers, or ventricles. When the heart relaxes, the ventricles refill with new blood.

An ejection fraction is the percentage of blood in a ventricle that is pumped out with each heartbeat. For instance, if your ejection fraction is 55 percent, it means 55 percent of the blood in the ventricle flows out with each heartbeat.

Ejection fraction usually represents the left ventricle only, so it’s often known as left ventricular ejection fraction (LVEF). That’s because the left ventricle is the heart’s main pumping chamber sending oxygen-rich blood to the body. Right ventricular ejection fraction (RVEF) is measured in people with right-sided heart failure, but this condition isn’t as common.

Measuring ejection fraction ranges is one way doctors can classify heart failure and better choose the most appropriate treatments. Newer definitions also recognize that ejection fraction cutoffs are not always exact and may vary based on factors such as age and sex. You may also see different classification systems depending on the medical guideline being used.

Heart failure can cause symptoms such as fatigue, shortness of breath, and leg swelling at any ejection fraction.

Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is heart failure in which the ejection fraction is usually 50 percent or higher. Ejection fraction alone can’t diagnose HFpEF. Doctors also look for heart failure symptoms and other signs that the heart is under abnormal pressure or isn’t working normally.

In this case, the heart may become stiff and have trouble filling with blood. Other changes in the heart, blood vessels, kidneys, and other parts of the body can also contribute.

Fluid can back up into the lungs, and the body may not receive enough oxygen-rich blood. This can cause mild symptoms at first, like more difficulty exercising, but can get worse.

Contributing factors to HFpEF include:

Heart Failure With Mildly Reduced Ejection Fraction

Heart failure with mildly reduced ejection fraction (HFmrEF) refers to heart failure with an ejection fraction of 41 percent to 49 percent in current U.S. treatment guidelines. However, a newer 2026 definition of heart failure no longer uses HFmrEF as a separate category.

This means the heart is pumping just below normal. People may have symptoms only with physical activity or also at rest.

Contributing factors to HFmrEF include:

Heart Failure With Reduced Ejection Fraction

Heart failure with reduced ejection fraction (HFrEF), also known as systolic heart failure, means the ejection fraction is 40 percent or below.

This means the heart isn’t pumping as strongly as it should. When the ejection fraction gets lower, the risk of life-threatening complications, such as cardiac arrest, can increase. People with HFrEF may have severe symptoms, even at rest.

Contributing factors of HFrEF can be similar to thsoe for HFmrEF but may also include:

Heart Failure With Improved Ejection Fraction

Heart failure with improved ejection fraction (HFimpEF) describes people whose ejection fraction was previously reduced but has since increased or returned to a normal range. Newer definitions also consider whether heart failure is improving, in remission, or has recovered.

This can happen when heart function improves with treatment and the heart pumps blood more efficiently than before. You may still have some symptoms, but your quality of life and risk of complications may be better.

High Ejection Fraction

A high ejection fraction of 75 percent or more is rare. It can happen in people with hypertrophic cardiomyopathy, a condition that causes the heart muscle to become abnormally thick.

Sometimes, dehydration (not drinking enough water) or an infection can also make ejection fraction unusually high for a short period of time.

Can Ejection Fraction Improve With Treatment?

A low ejection fraction can improve with treatments for the underlying cause. Appropriate treatments — including changes in self-care and, in some cases, surgery — can relieve symptoms, prevent complications, and slow the worsening of heart failure.

Medical Therapies by Ejection Fraction

For HFrEF, four main types of medications are standard treatments alongside diuretics, which are used to control fluid buildup:

People with HFmrEF may be treated with some of the same medications listed above. People with HFimpEF are generally advised to continue heart failure medications even if they no longer have symptoms or their ejection fraction improves.

For HFpEF, SGLT2 inhibitors can reduce the risk of worsening heart failure and hospitalization. Other treatments depend on a person’s health conditions and individual needs. Newer treatment options may also help some people with HFpEF.