What is “ejection fraction”?
Ejection fraction (EF) is a measurement, expressed as a percentage, of how much blood the left ventricle pumps out with each contraction. An ejection fraction of 60 percent means that 60 percent of the total amount of blood in the left ventricle is pushed out with each heartbeat.
This indication of how well your heart is pumping out blood can help to diagnose and track heart failure.
- A normal heart’s ejection fraction may be between 50 and 70 percent.
- You can have a normal ejection fraction measurement and still have heart failure (called HFpEF or heart failure with preserved ejection fraction).
- If the heart muscle has become so thick and stiff that the ventricle holds a smaller than usual volume of blood, it might still seem to pump out a normal percentage of the blood that enters it. In reality, though, the total amount of blood pumped isn’t enough to meet your body’s needs.
What’s too low?
- An ejection fraction measurement under 40 percent may be evidence of heart failure or cardiomyopathy.
- An EF from 41 to 49 percent may be considered “borderline.” It does not always indicate that a person is developing heart failure. Instead, it may indicate damage, perhaps from a previous heart attack.
- In severe cases, ejection fraction can be very low.
- Learn ways to improve your low ejection fraction.
What’s too high?
An ejection fraction measurement higher than 75 percent may indicate a heart condition such as hypertrophic cardiomyopathy.
Using ejection fraction in diagnosis
When examined using an echocardiogram, a significant number of patients with heart failure are revealed to have normal ventricular ejection fraction. This condition was previously called diastolic heart failure; it’s now referred to as heart failure with preserved ejection fraction.
Your doctor may mention one of these two EF-related scenarios:
- Preserved ejection fraction (HFpEF) – also referred to as diastolic heart failure. The heart muscle contracts normally but the ventricles do not relax as they should during ventricular filling (or when the ventricles relax).
- Reduced ejection fraction (HFrEF) – also referred to as systolic heart failure. The heart muscle does not contract effectively, and therefore less oxygen-rich blood is pumped out to the body.
Tests for measuring EF
Your doctor may recommend one or more of these tests to measure your ejection fraction:
- Echocardiogram (or “echo”) - the most widely used test
- MUGA scan
- CAT scan
- Cardiac catheterization
- Nuclear stress test
Learn more about common tests for diagnosing heart failure.