EF indicates to the percentage of blood pumped out of heart chamber during each heat beat (systole). EF or LVEF (Left Ventricular Ejection Fraction) refers to a measurement of the left ventricle (the lower left chamber of the heart), which pumps oxygen-rich blood out to the body through the aorta.
EF can be measured with the help of 2D ECHO with Colour Doppler test.
Even in a healthy heart, some blood always remains within the heart chambers after each heartbeat. Therefore an ejection fraction is a percentage of the blood within the chamber that is pumped out with every heartbeat. Normally, the left ventricle pumps 55 to 75 percent of the blood within that chamber out to the body with each heartbeat. A higher than normal ejection fraction could indicate the presence of certain abnormal condition such as hypertrophic Cardiomyopathy.
An ejection fraction of less than 40 may indicate heart failure, a chronic condition in which at least one heart chamber is not pumping well enough to meet the body's needs. Heart failure leads to congestion of blood vessels and fluid backup and swelling in the lungs, legs and ankles, shortness of breath, and fatigue. An ejection fraction between 40 and 50 percent may indicate damage to the heart muscle (e.g., from a prior heart attack). Typically, this EF level alone is not low enough to lead to heart failure. Ejection Fraction is one of the many ways doctors classify the type and severity of heart failure and damage to the heart muscle.