In cardiovascular physiology, ejection fraction (Ef) is the fraction of blood pumped out of a ventricle with each heart beat. The term ejection fraction applies to both the right and left ventricles; one can speak equally of the left ventricular ejection fraction (LVEF) and the right ventricular ejection fraction (RVEF). Without a qualifier, the term ejection fraction refers specifically to that of the left ventricle. Its reverse operation is the injection fraction.

http://en.wikipedia.org/wiki/Ejection_fraction

与左室舒张末径(LVDd)呈正相关(r=0.40，P<0.01)，与左室射血分数(LVEF)呈负相关(r=- 0.62.，P<0.01)。结论　NT-proBNP水平可以作为诊断心力衰竭的一个很好的指标，且心力衰竭患者血中的NT-proBNP水平随着心功能的恶化而增加，能较好地反映左室的功能。
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