Medical professionals use ejection fraction data to devise a course of treatment for heart problems based on heart function capacity, according to Mayo Clinic. Ejection fraction measures the percent of blood leaving the heart with each contraction.
Ejection fraction rates guide treatment plans to a certain extent. For example, ejection fraction of less than 40 percent confirms the presence of heart failure, notes Cleveland Clinic. The use of an implantable cardioverter defibrillator is indicated when ejection fraction falls below 35 percent.
The heart relaxes and contracts during each heartbeat cycle, and when it contracts, it ejects blood from both of its pumping ventricles, explains Mayo Clinic. When the heart relaxes, blood refills the ventricles. The ejection fraction measures how much blood pumps out with each beat of the heart. The main pumping chamber of the heart is the left ventricle, and ejection fraction generally measures only the pumping action of the left ventricle. Normal left ventricle ejection fraction rates of 55 percent or more are a normal reading, while rates below 50 percent indicate reduced capacity.
Ejection fraction is not the sole measure of heart function, states Mayo Clinic, and a normal ejection fraction does not necessarily indicate overall normal heart function. Typically, lowered ejection fraction indicates weakened heart muscle, problems with the valves of the heart, a previous heart attack or uncontrolled hypertension over the course of time.