What Is Ejection Fraction?
Anatomy of your heart
Your heart is a muscle. The left ventricle is the largest chamber of your heart. It needs to be a large, strong muscle. This is because its job is to pump blood through your entire body, including those of the lungs and heart.
Freshly oxygenated blood leaves your lungs and collects inside your left atrium. The left atrium contracts and pushes blood through the mitral valve. This is a valve between the left atria and the left ventricle. Blood fills the left ventricle which then contracts, forcing blood through your arteries and to all the tissues of your body.
What is ejection fraction?
A more specific name for it is left ventricular ejection fraction (LVEF). It measures how well your left ventricle is functioning. More specifically, it’s a measurement of how much blood is pushed out of your left ventricle into your arteries. It’s measured as a percentage. A normal ejection fraction is 50-70%. This means that, under normal circumstances (in healthy people), 50-70% of blood collecting in your left ventricle is pushed through your body.1
A weaker left ventricle
Certain disease states can cause the left ventricle to become a weaker pump. One disease that can do this is coronary artery disease (CAD). This is where cholesterol and plaque build-up in your arteries, making arteries abnormally narrow.
This may eventually lead to a condition called hypertension, or high blood pressure. High blood pressure is caused by arteries that are constricted or narrow. When this happens, your heart has to work extra hard to pump blood through blood your arteries.
When this goes on over a period of many years, your heart can become larger than normal. Hypertrophy is the medical term of an enlarged heart. A hypertrophied heart is a weaker heart. It cannot pump as forcefully as it used to. So, this is what causes a condition we call heart failure.
Different conditions and types of heart failure
Coronary artery disease is one condition that can cause heart failure. Others include heart attacks, kidney disease, kidney failure, lung diseases like COPD and cystic fibrosis, heart valves that do not open or close properly, etc.
When the left ventricle becomes a weaker pump, it has a hard time pushing out all of the blood that collects inside of it. When this happens it is diagnosed as left ventricular heart failure, or left heart failure. Often times it is simply referred to as heart failure.
Sometimes this affects the ejection fraction but not always, giving us two different types of left heart failure. Knowing the difference between the two is important because both have different treatments.
Diastolic heart failure
This is when the ejection fraction remains normal. What happens here is that the left ventricle contracts but it has a hard time completely relaxing. This prevents the left ventricle from filling completely. You can still have signs of heart failure with an EF greater than 45%. About half of people with heart failure have this type of heart failure.2-4
Systolic heart failure
In this case, the left ventricle does not contract very well. It is too weak to push all of the blood out of it. It is too weak to push enough blood through your body and the ejection fraction is less than normal. You have signs of heart failure with an EF of less than 45%.2-4
How do you determine your EF?
There are many different tests that can determine this: echocardiogram, cardiac catheterization, MRI, CT, and nuclear scan to name a few. The most common is an echocardiogram. This is an ultrasound test where a warm solution is placed on your chest. An ultrasonographer then waves a wand through this solution.
Ultrasonic waves from the wand put a picture of your heart on the screen. These pictures allow your doctor to see how well your heart valves are working and how well your left ventricle is functioning. They also give your doctor a value called an ejection fraction. As you now know, this gives your doctor a good idea of how well your left ventricle is functioning.5
A low ejection fraction can be improved
Your ejection fraction is an important number. It tells your doctor how well your left ventricle is functioning. It can also help diagnose whether you have systolic or diastolic heart failure. This is important because both of these conditions are treated differently. Also, a low ejection fraction can be improved by getting that proper diagnosis, seeing a qualified doctor, and getting proper treatment.6
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