Premature ventricular contractions are early beats that arise from the lower chambers of the heart.

室性早搏是指从心脏下心室产生的早搏。

Then there's the other kind of irregular heartbeat: Premature ventricular contractions are early beats that arise from the lower chambers of the heart.

还有另一种不规则的心跳: 室性期前收缩是由心脏下腔(左右心室)引起的早期心跳。

Atrial septal defect is a defect within the upper two chambers of the heart.

- 房间隔缺损是心脏上部两腔内的缺损。

This is the value that sits in between the chambers of the heart, the atrium and the ventricle.

这是位于心腔、心房和心室之间的值。

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

在极少数情况下，心律的突然变化会阻止心脏上腔的正常收缩。

The upper receiving chambers of the heart are the atria. The lower pumping chambers are the ventricles.

室间隔将两心室分开，房间隔将两心房分开。

It's very common for everyone to have an early beat arising from the upper chambers of the heart called premature atrial contractions, or PACs, once in a while.

每个人的上心室偶尔都会出现早搏即房性早搏（PACs），这是非常常见的。

Remember: The ventricles of the heart create very high pressure, while the atria, or the receiving chambers of the heart, have very little pressure, at least while the body's at rest.

心脏的心室产生非常高的压力，而心房或心脏的接收室压力很小，至少在身体休息时是这样。