I correct myself. EF can be calculated from NST. But echo is much better for estimation of EF

i googled this and this is what came up hope this will help you, but yes i would call or make a appointment with your heart dr and ask him or her about that Ejection fraction is a measurement of the percentage of blood leaving your heart each time it squeezes (contracts). It is just one of many tests your doctor may use to determine how your heart works.

The heart contracts and relaxes. When your heart contracts, it pumps out (ejects) blood from the two lower chambers (ventricles). When your heart relaxes, the ventricles refill with blood. No matter how forceful the contraction, the heart can never pump all blood out of a ventricle. The term "ejection fraction" refers to the percentage of blood that's pumped out of a filled ventricle with each heartbeat.

The ejection fraction is usually measured only in the left ventricle. The left ventricle is the heart's main pumping chamber. It pumps oxygen-rich blood up into your body's main artery (aorta) to the rest of the body.

A normal ejection fraction is about 50% to 75%, according to the American Heart Association.
A borderline ejection fraction can range between 41% and 50%.
Even if you have a normal ejection fraction, your overall heart function may not be normal. Talk with your doctor if you have concerns about your heart.

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Thank you

Nuclear stress tests do not measure EF. Not to my knowledge

Maybe you are referring to a summed stress score from the nuclear test. The test checks blood flow to the heart muscle, not ventricle ejection.

You must speak with your Cardiologist
My prayers for you to stay healthy