6 min read: Your ejection fraction is one useful measure of how the heart pumps, but it is not a percentage score of your overall heart health. Here is how to understand the number in context.
By Nachiket J. Patel, MD, FACC, FSCAI
Flow Heart & Vascular · Mesa, Arizona
You receive an echocardiogram report and see “ejection fraction 55%.” The number looks important, but the report may not explain what it means. Many patients assume it means their heart is working at only 55%. That is not what the number means.
Ejection fraction is an important part of an echocardiogram, but I never interpret it by itself. The rest of the images, your symptoms, your blood pressure, your heart rhythm, and whether the number has truly changed all matter.
What is ejection fraction?
Ejection fraction, often shortened to EF, estimates the percentage of blood that leaves the left ventricle each time it contracts. The left ventricle is the heart’s main pumping chamber.
For example, imagine the left ventricle contains 100 milliliters of blood just before it squeezes. If 60 milliliters leave during that heartbeat, the ejection fraction is 60%.
The ventricle is not supposed to empty completely. Some blood normally remains after each beat. An EF of 60% does not mean that 40% of the heart is failing.
What is a normal ejection fraction?
For most adults, an ejection fraction of about 55% to 70% is generally considered normal. An EF of 41% to 49% is often described as mildly reduced, while 40% or lower is considered reduced.
Those ranges are useful guideposts, not a diagnosis by themselves. Reference ranges can vary slightly by laboratory, imaging method, age, sex, and the quality of the study. A number just above or below a cutoff should be interpreted with the rest of the echocardiogram and the reason the test was ordered.
Does a low ejection fraction mean I have heart failure?
It can be a sign of heart failure or cardiomyopathy, but the number alone does not tell the whole story. Some people have a reduced EF before they develop obvious symptoms. Others have shortness of breath, swelling, fatigue, or reduced exercise tolerance.
When the EF is low, I want to know why. Possible causes include:
- Coronary artery disease or a previous heart attack
- Long-standing high blood pressure
- Heart valve disease
- A persistent fast or irregular heart rhythm
- Inflammation of the heart muscle
- Certain medications, toxins, or cancer treatments
- An inherited heart-muscle condition
The cause matters because some forms of reduced heart function can improve substantially with treatment. Others need long-term medication and monitoring even when the EF later improves.
Can I have heart failure with a normal ejection fraction?
Yes. This is called heart failure with preserved ejection fraction, often shortened to HFpEF.
In HFpEF, the heart may squeeze out a normal percentage of the blood inside it, but the muscle can be thick or stiff and may not relax normally. Pressure can build inside the heart and lungs, leading to shortness of breath, swelling, fatigue, or difficulty exercising.
A normal EF therefore does not rule out heart failure. The diagnosis depends on the symptoms, examination, blood tests, chamber size, wall thickness, valve function, filling pressure clues, and sometimes additional testing.
Why did my ejection fraction change between tests?
A change can be real, but not every difference means that the heart has become weaker or stronger.
The measurement can vary because of:
- Image quality
- The views obtained during the study
- Heart rhythm at the time of the test
- Blood pressure and fluid status
- How the ventricle was measured or traced
- Differences between echocardiography, cardiac MRI, and nuclear imaging
For example, a change from 55% to 50% does not automatically prove that heart function has worsened. I would want to review the actual images, the measurement method, the rest of the report, and how the patient is feeling. A larger or repeated change, especially with new symptoms, deserves closer attention.
What else on the echocardiogram matters?
The EF is only one part of the study. I also look at:
- The size and thickness of the heart chambers
- Whether all areas of the heart muscle move normally
- How the heart relaxes and fills
- Whether a valve is narrowed or leaking
- Right ventricular size and function
- Pressure clues in the heart and lung circulation
- The aorta and the tissue surrounding the heart
- How the study compares with prior images
A patient can have a normal EF and still have important valve disease, abnormal filling pressure, or a problem involving the right side of the heart. A mildly reduced EF can also be stable and may not explain the symptom that led to the test.
Can ejection fraction improve?
Yes. Heart function may improve after treatment of high blood pressure, coronary disease, a rhythm problem, valve disease, or another cause of cardiomyopathy. Heart-failure medications can also help the heart recover in appropriate patients.
An improved number does not always mean the underlying condition has disappeared. Some patients remain at risk even after the EF returns to a normal or near-normal range. Do not stop a heart-failure or blood-pressure medicine simply because a later echocardiogram looks better. Medication changes should be made with the clinician who knows why the medicine was prescribed.
Should my echocardiogram be repeated?
Not everyone needs a repeat study simply because time has passed. The timing depends on why the first echocardiogram was done, whether symptoms have changed, whether treatment was started or adjusted, and whether there is a valve or heart-muscle condition that needs surveillance.
A repeat test is most useful when the result could change the plan. If the number in the report concerns you, ask whether the actual images were compared with the prior study and whether the difference is large enough to matter.
What should I ask about my result?
- Is my ejection fraction normal for this study?
- How does it compare with my previous echocardiogram?
- Is the change likely to be real or within normal measurement variation?
- What else on the echocardiogram is important?
- Does the result explain my symptoms?
- Does it change my medication, testing, or follow-up plan?
- When, if ever, should the echocardiogram be repeated?
When seeking a second opinion, bring the actual echocardiogram images when possible, not only the written report. The images often provide information that cannot be reconstructed from one number.
When should I seek urgent care?
The EF number itself is rarely an emergency. Symptoms can be.
Call 911 for new or severe chest pressure, severe shortness of breath at rest, fainting, blue or gray lips, facial droop, arm weakness, speech difficulty, or another sudden major change. Rapidly worsening swelling, new breathlessness at rest, or an inability to lie flat comfortably also deserves prompt medical attention.
Dr. Patel’s bottom line
Ejection fraction is useful, but it is not a report card for the entire heart. An EF of 55% does not mean the heart is working at only 55%. A normal EF does not rule out every heart problem, and a low EF does not tell us the cause.
What matters is how the number fits with the rest of the echocardiogram, your symptoms, your prior studies, and the plan going forward.
Related heart and vascular information
- Echocardiogram
- Congestive Heart Failure
- Heart Valve Disease
- Shortness of Breath
- Cardiology Second Opinions
Request an appointment
At Flow Heart & Vascular in Mesa, Arizona, I can review your echocardiogram in the context of your symptoms, prior images, medications, and cardiovascular history.
Call 480-571-1863 or request an appointment. Patients who want another interpretation of an existing study may also ask about a cardiovascular second opinion.
This article provides general education and does not replace individualized medical advice, diagnosis, or emergency care. Do not start, stop, or change a medication based only on information on this website.
Sources and further reading
- American Heart Association: Ejection Fraction Heart Failure Measurement
- AHA/ACC/ESC/WHF: Second Universal Definition of Heart Failure, 2026
- AHA/ACC/HFSA: 2022 Guideline for the Management of Heart Failure
- American Society of Echocardiography: Evaluation of Left Ventricular Diastolic Function and HFpEF, 2025
