Ejection fraction (EF) is a percentage-based measurement of how much blood leaves the heart when it beats. It can be used to evaluate or diagnose heart failure and some other kinds of cardiovascular disease. When speaking of ejection fraction it is often preceded by different terms to provide clarity. Here’s a look at what the heart EF is, why ventricular ejection fraction is measured, and an explanation of the ranges of ejection fractions.
Heart Ejection Fraction
To understand EF, it’s important to understand how the heart works. Your heart consists of four chambers: two upper atrium and two lower ventricles. The blood that has been floating around your body and is now devoid of key nutrients and oxygen enters the right atrium, goes down to the right ventricle, and from there to the lungs. The lungs re-oxygenate the blood and return it to the left atrium. From there, the blood is sent into the left ventricle and then back into the body to provide fresh oxygen to the muscles, organs, and other body parts seeking sustenance.
When the heart contracts, the ventricles release blood; when it relaxes, the ventricles are filled. Nobody’s heart ever completely empties of blood. However, the amount of blood that leaves it can be indicative of damage or disease in the heart. Doctors use ejection fraction to see not only if heart failure may be a concern but also how significantly the heart failure is progressing.
Ventricular Ejection Fraction
In particular, ejection fraction is the measure of how much blood leaves the left ventricle (LV). According to the Mayo Clinic, EF is generally based on the LV because it is the ventricle responsible for providing replenished blood to the body. Not enough blood leaving the LV means there is an insufficiency of blood all over the body.
Ventricular EF can be diagnosed in a variety of ways using imaging technology. The most common utilizes ultrasound technology called an echocardiogram. Using a wand-shaped transducer on the chest, real-time images of the heart are sent to a computer screen, allowing your cardiologist to watch your heart contract and release, thereby evaluating the percentage of your ejection fraction.
Levels of Ejection Fraction
According to the American Heart Association, a normal ejection fraction is generally around 50-70%. If you have an ejection fraction of 55%, this means that with each pump, your heart ejects 55% of the blood in the ventricle in question. Thus, the term ejection (eject) fraction (the percentage out of 100). However, it is important to note that some forms of heart failure -- formerly diastolic heart failure, but now considered heart failure with normal or preserved EF -- still show a normal ejection fraction. The heart can’t hold a normal amount of blood, so though it releases what seems a normal amount, something is still amiss.
Between 41 and 40% is considered a lower than normal ejection fraction. It is not necessarily indicative of heart failure but may be more likely to show sustained damage from a heart attack or other seemingly less serious issue. A low EF begins when the percentage falls under 40%. Low EF can be a sign of heart failure and should be taken seriously. Additionally, if your ejection fraction is above 75%, it is considered a high ejection fraction and can be suggestive of hypertrophic cardiomyopathy.
