That is reassuring. But what about the other bad beats, the premature contractions in the heart's lower chambers?

就让人放心了。那其他有害心跳，发生心脏下期前收缩(室性期前收缩)呢?

This is the term used to describe the contraction of the heart.

是用来描述心脏收缩术语。

It would squeeze the capsule tightly as the heart contracted and still keep a firm grip on it when the heart was relaxed.

它可以随着心脏收缩轻微挤压胶囊，且心脏放松时，也能紧紧抓住。

On rare occasions, a sudden change in heart rhythm prevents the upper chambers of the heart from contracting normally.

极少数情况下，心脏节律突然变化会妨碍心脏正常收缩。

This is a term used to describe the contraction of the heart.

是一个用来描述心脏收缩术语。

Frank and Starling were looking at the amount of blood in the heart before the ventricles contract.

Frank 和Starling正观察心室收缩前心脏流量。

This ability is thanks to the intrinsic conduction system, which is the internal regulating system that causes the heart to contract rhythmically.

种能力是由于内传导系统，是导致心脏有节奏收缩内部调节系统。

This ability is thanks to the intrinsic conduction system, which is defined as the internal regulating system that causes the heart to contract rhythmically.

种能力归功于内传导系统，内传导系统被定义为使心脏有节奏地收缩内部调节系统。

That's right - a healthy heart does not pump every last drop of blood out of the ventricles when they contract no matter how strongly they contract.

没错，一个健康心脏收缩时候不会把每一滴从心室中泵出，不收缩多厉害。

And what we found was that stimuli that occurred during heart's contraction were perceived to last shorter than stimuli that occurred between the beats, when the heart was relaxed.

我们发现，心脏收缩期间发生刺激持续时间比心脏放松时两次心跳之间发生刺激持续时间短。

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缩，所以些药物也会减弱心脏收缩力，因此收缩性心力衰竭患者不应该使用该类药物。