With every heartbeat, your heart muscle contracts and then relaxes. When your heart relaxes, it fills up with blood. Every time it contracts, your heart pushes out blood to meet the demands of your body. But, the heart doesn’t pump out all of the blood with each contraction. Some blood stays in the heart each time. The percentage of blood pumped out is your heart ejection fraction (EF).
For example, an ejection fraction of 60% means your heart is pumping out 60% of its blood with each heartbeat. This ejection fraction heart failure measurement tells your doctor how well your heart is working. The ejection fraction also helps doctors monitor heart failure and track its progression. Remember, even a healthy heart won’t pump out 100% of the blood in it.
How is ejection fraction measured?
Doctors usually use a simple test called an echocardiogram—or echo, for short—to measure ejection fraction. The test uses painless sound waves to create a video of your heart. It provides information about the size and shape of your heart, and how it functions. An echo can show if the blood flow to your heart is lower than it should be. It will also show if your heart isn’t pumping as well as it should.
What does a normal ejection fraction mean?
With every heartbeat, slightly more than half of the blood in the heart is pumped out into the body. A healthy heart pumps 50 to 75% of its blood volume every time it contracts. A number in this range would be a normal EF.
You can have a normal EF but still have heart failure. The medical term for this condition is heart failure with preserved ejection fraction (HFpEF). Another name is diastolic heart failure. This condition develops when the heart muscle becomes so thick and stiff it doesn’t relax properly. When this happens, the heart fills up with less blood. It can look like it's pumping a normal percentage of blood. But in reality, it’s not enough blood to supply the body because the total volume of blood in the heart is smaller.
What does a low ejection fraction mean?
A low ejection fraction can signal that the heart muscle isn't contracting properly. When this happens, the heart pumps less blood out to the body. This is systolic heart failure. The medical term for a low ejection fraction is heart failure with reduced ejection fraction (HFrEF).
An ejection fraction of 36 to 49% means the heart’s pumping ability is below normal. This can be an early sign of heart failure. It means the heart is weak and not working as well as it should. People with a low ejection fraction may have a rapid heartbeat. They may also develop warning signs of heart failure, such as shortness of breath and swelling in the feet, legs and ankles.
In people with an ejection fraction heart failure measurement—35% or lower—the heart’s ability to pump blood to the body has become very low.
What does a high EF mean?
It’s also possible for heart ejection fraction to be too high. An ejection fraction higher than 75% could be a sign of another heart problem, such as hypertrophic cardiomyopathy. This condition occurs when stiff or thickened heart muscle reduces the amount of blood the heart is able to hold. This is a situation similar to HFpEF.
