Ejection Fraction

Ejection fraction (EF) is the percentage of blood your heart’s lower left chamber (left ventricle) pumps out, or ejects, with each beat. The number tells how well and how efficiently your heart can pump blood. A normal ejection fraction is 50% to 70%. With each heartbeat, 50% to 70% of the blood in your left ventricle goes out to your body.

A number lower than 50% means your heart isn’t pumping as well as it should. A low EF is a sign of heart failure and other problems. The lower the ejection fraction, the weaker your heart’s pumping action is. Different treatments can help, depending on how far from normal your ejection fraction is.

Ejection fraction typically refers to the left side of your heart (left ventricular ejection fraction, or LVEF). It shows how much oxygen-rich blood your left ventricle pumps out to most of your body’s organs with each contraction. LVEF helps define how badly or how well the left side of your heart is working.

Healthcare providers can also take measurements on the right ventricle (right ventricular ejection fraction, or RVEF). This measures the amount of oxygen-poor blood the right side of your heart pumps out to the lungs for oxygen. It’s important if you have right-sided heart failure. But this condition isn’t as common as left-sided heart failure.

What is the ejection fraction formula?

The ejection fraction (EF) formula is EF = (SV/EDV) x 100. The last step (multiplying by 100) allows you to show this as a percentage.

• Ejection fraction, or EF: The percentage of blood that comes out of the ventricle after a contraction
• Stroke volume, or SV: The amount of blood your ventricle pumps out with each contraction
• End-diastolic volume, or EDV: The total amount of blood in the ventricle after it relaxes and fills

How is this measured?

There are a few methods for measuring ejection fraction. An echocardiogram is the most common.

Other heart tests that measure ejection fraction include:

• Cardiac catheterization
• Cardiac computed tomography (CT) scan
• Heart MRI
• Nuclear cardiac imaging, like MUGA, SPECT or PET

What does it mean if my EF isn’t within the normal range?

An ejection fraction outside of the normal range could mean a variety of things:

• 40% to 49% is mildly reduced ejection fraction: Your heart’s pumping ability is slightly below normal. You might not have heart failure symptoms. Or you may have symptoms only with physical activity.
• 39% or less is heart failure with reduced ejection fraction (HFrEF): Pumping ability is below normal. The lower the EF, the higher the risk of life-threatening complications, like cardiac arrest. Symptoms may be severe and may affect you even when sitting still.

Some people with a normal ejection fraction also have heart failure. This is known as heart failure with preserved ejection fraction (HFpEF), or diastolic heart failure.

With HFpEF, the left ventricle holds a lower volume of blood. This is often because thick or stiff heart tissue shrinks the ventricle size. When this happens, the amount of blood that goes out to the body isn’t enough to meet its needs.

You may be at risk for heart failure with preserved ejection fraction if you have:

• Cardiac tamponade
• Coronary artery disease
• Heart valve disease
• High blood pressure
• Sleep apnea

What causes reduced ejection fraction?

Conditions that weaken or damage heart muscles make their contractions incomplete and less effective. You need healthy muscles in your lower heart chambers so they can pump blood well.

Your heart may compensate by working harder to do its job. The extra work can lead to swelling or scar tissue buildup that affects the ventricles’ ability to fill and pump. You might not feel the effects of a slightly reduced ejection fraction. But as your heart function declines and your ejection fraction worsens, you can become severely ill.

What does it feel like to have a low EF?

The lower your ejection fraction, the more severe your heart failure symptoms may be. You might have:

• Confusion
• Fatigue
• Heart palpitations
• Nausea
• Shortness of breath (dyspnea)
• Water retention in your belly or feet
• Weakness
• Loss of consciousness
• Dizziness
• Difficulty breathing while lying down (orthopnea)

What happens if my ejection fraction is higher than average?

An ejection fraction of 75% or more is rare. It can occur in people with hypertrophic cardiomyopathy. In these cases, a dangerously high EF needs medical care. Sometimes, your EF can be temporarily elevated when you’re dehydrated or sick (like with an infection).

How is my EF used to guide treatment?

Your ejection fraction is a sign of how well your heart is working. A low ejection fraction typically means you have or are at risk for heart failure. EF helps healthcare providers decide which heart failure treatment is best for you. Checking ejection fraction throughout therapy shows whether your heart function is improving.

It’s helpful to know your ejection fraction if you have or are at risk for a condition that can lead to heart failure.

These conditions include:

• ATTR amyloidosis, which can affect your heart
• Cancer or other conditions that need chemotherapy, which sometimes causes heart damage (cardiotoxicity)
• Heart disease you have at birth (congenital heart disease)
• Heart attack
• Heart valve disease
• Heart muscle problems (cardiomyopathy)
• Myocarditis
• Severe high blood pressure
• Ventricular arrhythmia

How can I improve my ejection fraction?

Heart failure therapies treat the underlying cause of low ejection fraction. For heart failure due to an abnormal heart rhythm, a biventricular pacemaker may help. If you have heart failure from other causes, like high blood pressure, you may need medications.

There are also specific medications shown to improve EF that your healthcare provider will prescribe regardless of the cause of low ejection fraction.

You can take other steps to relieve strain on your heart and get the most out of treatment. These include:

• Increasing physical activity, like starting a cardiac rehab program
• Maintaining a weight that’s healthy for you
• Limiting the amount of sodium and fluids you consume
• Quitting the use of tobacco, substances and alcohol

How will I know if my EF is improving?

If your symptoms are fading, it may be a sign that your ejection fraction is improving. You’ll have frequent appointments with your healthcare provider to monitor a low ejection fraction.

It’s essential to go to all appointments, even if you don’t feel sick. Symptoms can worsen or new ones can appear. These issues may be signs of a worsening ejection fraction.

Contact your healthcare provider right away if you have:

• Difficulty breathing, especially when lying down
• A heartbeat that feels unusually fast
• Loss of appetite or vomiting
• Sudden weight change, which could be a sign of fluid retention
• Unexplained weakness or dizziness

How often should my ejection fraction be measured?

The frequency of testing after a heart failure diagnosis depends on a variety of factors, including how low your first ejection fraction reading was. If your EF keeps getting worse, you’ll need it checked more often. If it’s stable, you might not need it checked as often.

Healthcare providers may be concerned about your ejection fraction if you:

• Have symptoms of heart failure
• Have a heart attack or other condition that affects heart function
• Are living with a condition that raises the risk of heart failure

Is EF the only test for heart failure?

Ejection fraction is one of many ways your healthcare providers assess heart failure. Other tests make it possible to pinpoint the cause so you receive the right care.

These tests may include:

• Angiography
• Chest X-ray
• Echocardiogram
• Electrocardiogram (ECG/EKG)
• Exercise stress test
• Cardiac MRI