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在50-70％，40-50％底线，任何低于40%的射血分数指示收性心力衰竭，也就说在心脏在每次搏动中只输出了少量血液。

But when it came to constrictive bronchiolitis — the disease Miller believed he found in his biopsies — the agency stymied his efforts to create a criterion, he says.

但当涉及到收性支气管炎——米勒认为他在活检中发现的疾病——该构阻碍了他制定标准的努力，他说。

More demand and reduced supply means that some of the ventricular muscle starts to have weaker contractions —leading to systolic failure.

需求增大而供血减少，意味着一些心肌开始虚弱地收，导致收性心衰。

Now in addition to systolic heart failure, you've also got diastolic heart failure, which is where the heart's squeezing hard enough but not filling quite enough.

除收性心衰外，还有舒张性心力衰竭，指的心脏收正常，但在舒张期充盈受损。

This can happen in two ways, either the heart's ventricles can't pump blood hard enough during systole, called systolic heart failure, or not enough blood fills the ventricles during diastole, called diastolic heart failure.

这可以两种方式发生：一种心室在心脏收期不足够有力地泵出血液，即收性心力衰竭；另一种在心脏舒张期心室充盈不足，即舒张性心力衰竭。

Even though systolic failure is most common in left-sided heart failure, diastolic heart failure or filling dysfunction can also happen.

尽管收性心衰左侧心力衰竭最主要病因，舒张性心力衰竭或充盈障碍也有可发生。

Food is propelled by rhythmic contractions of muscles in the wall of the esophagus.

食物被食管壁肌肉通过节律性的收推动。

These drugs bind to and block the fast sodium channels that are responsible for the depolarizing phase and contractile myocytes.

这些药结合并阻断快钠通道。快钠通道作用于去极化时相和有收性的心肌。

However because calcium is also involved in cardiac myocyte contraction, these agents also reduce contractility of the heart and should not be used in case of systolic heart failures.

然而，因为钙通道也参与了心肌收，所以这些药物也减弱心脏的收力，因此收性心力衰竭患者不应该使用该类药物。