The left ventricular ejection fraction (LVEF) is a measure of the heart’s ability to pump blood. It is measured by echocardiography (ECHO) and is used to diagnose and monitor heart failure. High or low LVEF values suggest the heart is not working properly.
The heart is a four-chambered organ with two atria and two ventricles. The right side of the heart pumps blood to the lungs, where the blood can pick up oxygen and release carbon dioxide. After circulating through the lungs, the blood returns to the left side of the heart. The blood is then distributed through the rest of the body by the pumping of the left ventricle.
The left ventricular ejection fraction is a measurement used to assess the function of the heart. By definition, the left ventricular ejection fraction is the amount of blood pumped out of the heart divided by the left ventricular volume prior to the heart’s contraction. It represents how much of the blood pooled in the left ventricle can be sent from the heart to the body. It reflects the heart’s contractility, or strength. Normal LVEF values range from 55 percent to 80 percent for resting patients, with an average value of 67 percent.
The LVEF is typically determined using echocardiography. This imaging technology uses sound waves to provide a real-time picture of the heart as it progresses through cycles of resting and pumping. Echocardiographers can determine the left ventricular ejection fraction by visual assessment of the two-dimensional images showing blood flow leaving the left ventricle.
Having a low left ventricular ejection fraction usually means the heart cannot pump blood as effectively as a healthy heart can. It is often a finding associated with left ventricular failure. In fact, patients with low LVEFs are considered to have heart failure even if they have no clinical symptoms suggestive of the condition. Once diagnosed with heart failure, patients typically get regular echocardiograms to monitor for decreases in the LVEF. Declining LVEF levels might suggest a need for more aggressive therapies.
High left ventricular ejection fractions can also suggest the presence of heart disease. Values greater than 80 percent often indicate a dysfunction of the resting heart. In this pathological state, the muscle of the heart becomes rigid and the filling of the left ventricle from the left atrium is impaired. The left ventricle is able to pump the blood it receives, as evidenced by the high left ventricular ejection fraction. This amount of blood, however, is insufficient, and the body suffers from a lack of oxygenated blood from the heart.