What is ejection fraction?
Ejection fraction (EF) refers to how well your left ventricle (or right ventricle) pumps blood with each heart beat. Most times, EF refers to the amount of blood being pumped out of the left ventricle each time it contracts. The left ventricle is the heart's main pumping chamber.
Your EF is expressed as a percentage. An EF that is below normal can be a sign of heart failure. If you have heart failure and a lower-than-normal (reduced) EF (HF-rEF), your EF helps your doctor know how severe your condition is.
Left ventricular ejection fraction (LVEF) is the measurement of how much blood is being pumped out of the left ventricle of the heart (the main pumping chamber) with each contraction.
Right ventricular ejection fraction (RVEF) is the measurement of how much blood is being pumped out of the right side of the heart to the lungs for oxygen.
In most cases, the term “ejection fraction” refers to left ventricular ejection fraction.
How the Heart Works
A healthy heart beats about 60 to 80 times per minute to pump blood throughout the body. The right and left sides of the heart work together. Blood that is low in oxygen first enters the right upper chamber (right atrium) of the heart. The blood flows from the right atrium to the lower chamber (right ventricle) through the open tricuspid valve. Blood passes through a valve before leaving each chamber of the heart. There are four valves in your heart; valves make sure blood flows in only one direction through your heart. The blood then travels through the pulmonary artery to the lungs where oxygen is added.
Oxygen-rich blood then returns to the left side of the heart. The blood flows from the left upper chamber (left atrium) to the lower chamber (left ventricle) through the open mitral valve. From the left ventricle, the blood is pumped into a network of arteries (blood vessels) that carry the blood throughout the body. Learn more about blood flow through the heart.
How is EF measured?
Ejection fraction can be measured using:
- echocardiogram (echo) - this is the most common way to check your EF
- magnetic-resonance-imaging-mri (MRI) scan of the heart
- Nuclear medicine scan (multiple gated acquisition [MUGA]) of the heart; also called a nuclear stress test
Why it is important to know your EF
If you have a heart condition, it is important for you and your doctor to know your ejection fraction. Your EF can help your doctor determine the best course of treatment for you. Measuring your EF also helps your healthcare team check how well our treatment is working.
Ask your doctor how often you should have your EF checked. In general, you should have your EF measured when you are first diagnosed with a heart condition, and as needed when your condition changes.
What do the numbers mean?
If you have heart failure it means that your heart is not working as well as it should. A normal left ventricular ejection fraction (LVEF) ranges from 55% to 70%. An LVEF of 65%, for example means that 65% of total amount of blood in the left ventricle is pumped out with each heartbeat. Your EF can go up and down, based on your heart condition and how well your treatment works.
- Ejection Fraction (EF) %: 55% to 70%
- Pumping Ability of the Heart: Normal
- Level of Heart Failure/Effect on Pumping: Heart function may be normal or ou may have heart failure with preserved EF (HF-pEF).
- Ejection Fraction (EF) %: 40% to 54%
- Pumping Ability of the Heart: Slightly below normal
- Level of Heart Failure/Effect on Pumping: Less blood is available so less blood is ejected from the ventricles. There is a lower-than-normal amount of oxygen-rich blood available to the rest of the body. You may not have symptoms.
- Ejection Fraction (EF) %: 35% to 39%
- Pumping Ability of the Heart: Moderately below normal
- Level of Heart Failure/Effect on Pumping: Mild heart failure with reduced EF (HF-rEF).
- Ejection Fraction (EF) %: < 35%
- Pumping Ability of the Heart: Severely below normal
- Level of Heart Failure/Effect on Pumping: Moderate-to-severe HF-rEF. Severe HF-rEF increases risk of life-threatening heartbeats and cardiac dysynchrony/desynchronization (right and left ventricles do not pump in unison).
Heart Failure Types
There are two main types of heart failure.
Heart failure with preserved left ventricular function (HF-pEF). If you have HF-pEF, your EF is in the normal range because your left ventricle is still pumping properly. Your doctor will measure your EF and may check your heart valves and muscle stiffness to see how severe your heart failure is.
Heart failure with reduced left ventricular function (HF-rEF). If you have an EF of less than 35%, you have a greater risk of life-threatening irregular heartbeats that can cause sudden cardiac arrest/death. If your EF is below 35%, your doctor may talk to you about treatment with an implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy (CRT). Your doctor may also recommend specific medications or other treatments, depending on how advanced your heart failure is. Less common treatment options include a heart transplant or a ventricular assist device (VAD). If your quality of life is very poor or your doctor has told you that your condition is very severe, please ask about other possible treatments.