Ejection Fraction at Medical City Plano
Every time your heart contracts and relaxes, a percentage of blood leaves the heart. An ejection fraction (EF) numerically measures the percentage of blood lost with each heart contraction.
During a heartbeat cycle, the heart contracts and ejects blood from the two pumping chambers, called ventricles. As your heart relaxes, the ventricles fill up again with blood. No matter how forceful a contraction is, there is still blood left in the ventricles, and the ejection fraction number determines the amount of blood that's pumped out with each contraction.
Ejection fraction is usually only measured in the left ventricle — your heart's main pumping chamber. An ejection fraction ranging from 55 to 75 percent is considered normal, and the fraction may increase if you have a weakened heart muscle, have had a heart attack, have high and uncontrolled blood pressure, or have heart valve problems. A high EF might mean you're at risk for certain heart conditions, including hypertrophic cardiomyopathy. A low EF percentage might mean you have a weak heart, or indicate you have an enlarged, thickened or stiffened heart. Low EF is an important indicator of sudden cardiac death as well.
Measuring Ejection Fraction
Ejection fraction is most commonly measured during an echocardiogram, a painless and noninvasive test that uses high-frequency ultrasound waves to produce images of the four heart chambers and valves, as well as images of blood pumping though the heart.
Other imaging techniques used to measure ejection fraction include:
- Cardiac catheterization, performed by inserting a thin plastic tube, or catheter, into a vein in the leg or arm. The catheter is then internally moved to the heart to capture images of blood pumping.
- Computerized tomography (CT), a scan that uses special X-ray techniques to capture cross-sectional images of the body part being scanned.
- Magnetic resonance imaging (MRI), which uses magnetic fields and radio waves to capture cross-sectional images of certain parts of the body being scanned.
- Nuclear medicine scan, during which a small amount of radioactive material, such as thallium, is injected into the bloodstream and detected using special cameras that document blood flow through the heart.