The heart is a strong muscular pump. The heart pumps blood to nourish all parts of the body, including itself. It is responsible for pumping about 3,000 gallons of blood throughout the body every day. The blood that nourishes the heart muscle flows through the coronary arteries. Coronary artery disease is caused by atherosclerosis, which is a gradual buildup of plaque and fatty material inside the arteries. As the arteries narrow, less blood flows to the heart muscle. If a clot plugs one of these arteries or blood flow decreases enough, the muscle, starved for oxygen, dies and a heart attack takes place. Like other muscles in the body, the heart itself needs to receive a good supply of blood at all times to function properly.

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.

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.

An Ejection Fraction above 50 percent indicates that your heart is pumping normally and able to deliver an adequate supply of blood to your body and brain.

An Ejection Fraction that falls below 50 percent could indicate that the heart is no longer pumping efficiently and not able to meet the body's needs.

An Ejection Fraction of 35 percent or less indicates a weakened heart muscle and that the heart is pumping poorly, which can significantly increase a person's risk for sudden cardiac arrest (SCA).

Recent medical research shows that people with an Ejection Fraction of 35% or lower may be at increased risk of SCA. If you have a low Ejection Fraction, your doctor may prescribe medications; recommend change in the life style and diet or may suggest other therapies.

A low ejection fraction may result from some kind of Cardiomyopathy, a condition in which the heart is abnormally enlarged, thickened or stiffened. Low EF is an important risk factor for sudden cardiac death (SCD), a condition that occurs when the heart stops abruptly (cardiac arrest), usually as a result of ventricular fibrillation. Patients with a low EF are significantly more likely to suffer sudden cardiac death within two years than patients with a normal ejection fraction.