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A body's ejection fraction refers to the measure of blood that the heart pumps with each contraction from its two ventricles. Ejection from the left and right ventricles can be measured, though it is the left ventricle reading that concerns most physicians. A depressed ejection fraction of below 50 percent may indicate recent heart failure, with lower scores signaling the onset of heart disease. A preserved ejection fraction, by contrast, is above 50 percent and means the body is getting the oxygenated blood it needs to keep trudging on.
A range of tests can measure whether the heart has a preserved ejection fraction. Physicians regularly use ultrasound technology, called an echocardiogram, to gauge these levels. Other methods may include catheterization, a computerized tomography (CT) scan or magnetic resonance imaging (MRI). Doctors use the scores for preventative measure, after heart failure to gauge the proper treatment, and during treatment to gauge improvements.
According to the Cleveland Clinic, preserved ejection fraction levels range from 50 percent to 70 percent. Less than normal is 36 percent to 49 percent, which may indicate a recent episode of heart failure that damaged the heart. Between 35 percent and 40 percent, according to the Cleveland Clinic, could mean near-eminent systolic heart failure, and below 35 percent is indicative of a dangerous irregular heartbeat that often leads to a heart attack.
Studies show that about half of the patients suffering heart failure had a depressed ejection fraction of less than 40 percent. With a preserved ejection fraction, patients tended to be older women suffering from hypertension and not coronary artery disease. These patients, studies reveal, are more likely to recover from heart failure than those with a depressed ejection fraction.
The less preserved ejection fraction is more likely to trigger a doctor to recommend invasive action. Often this means catheter surgery; other times, an implantable cardioverter defribrillator (ICD) is needed. Several medications for heart disease — designed to lower cholesterol and blood pressure — are another likely course of treatment.
During testing after heart failure, doctors will attempt to diagnose which of the two types of problems exist. With systolic failure, the left ventricle is not beating — or contracting — with sufficient vigor, meaning that less oxygen is reaching the body's cells. When diastolic heart failure has occurred, the heartbeat may be normal and a preserved ejection fraction is likely. The ventricles, however, may be stiff and inflexible, making it difficult for the heart to process the amount of blood needed.