Several heart conditions and untreated high blood pressure can cause changes in the heart ejection fraction rate, according to Mayo Clinic. Ejection fraction is just one method of measuring heart function, and even someone with a normal rate can have heart disease.
The ejection fraction rate may decrease if heart or vascular conditions are present, Mayo Clinic states. These conditions include heart attack, a problem with the heart's valves, weak heart muscles or long-term, uncontrolled high blood pressure.
The ejection fraction rate measures the percentage of blood pumped out of the heart each time it contracts, Mayo Clinic explains. During each pause between heartbeats, the ventricles fill with blood. No matter how strong a person's heart, not all of the blood is pumped out during one contraction.
The left ventricle is the primary pumping chamber, so it is the focus of the test, Mayo Clinic says. An ejection fraction rate out of the left ventricle of 55 percent is considered normal. Below 50 percent is considered decreased, and some doctors consider between 50 and 55 borderline.
A variety of tests can measure ejection fraction rate, Mayo Clinic reports. They include nuclear medicine scans, computerized tomography, MRIs, cardiac catheterization and echocardiograms.