In this case again the stroke volume is low, but the ejection fraction's normal... how's that?

在这种情况下，每搏输出量低，但射血分数显示正常，为什么会这样呢？

Her MUGA had an ejection fraction of 19% with no focal wall motion abnormalities.

放射性核素活动血管扫描结果提示射血分数为19％无局部心室壁运动异常。

A normal ejection fraction is around 50-70%, between 40-50% would be borderline, and anything about 40% or less would indicate systolic heart failure because the heart is only squeezing out a little blood each beat.

正常的射血分数大约是在50-70％间，40-50％会是底线，任何低于40%的射血分数指示收缩性心力衰竭，也就是说在心脏在每次搏动中只输出了少量血液。