And this is how you could tell if the PVC depolarized the atrium or not.

你能由此区分室期前收缩是否除极了心。

And, to the degree that the heart's in-between, the heart will be depolarized and normal rhythm will, will be restored.

当心脏处于这两者之间时，心脏会去极化，恢复正常的心律。

The cells of the SA node can depolarize on their own without any external influence.

SA结细胞可以自行去极化而不受外界影响。

Ectopic beats can also have “triggered activity” which is where cells depolarize early.

异位心搏也有“激发活动”，即在细胞提前除极的位置。

Another type of atrial ectopic focus is a reentrant loop, which is when there’s some tissue that doesn’t depolarize right.

异位起搏点是个折返环路，主要发生在当某些组织不能正确地除极的时候。

In this case, after being depolarized, the sinus node waits its 1 second, and then sends another signal and again we carry on as normal.

在这种情况下，窦结在除极之后等待了1秒，然后发放个信号，心搏得以重新正常进行。

Now, if we measure out the interval between each SA node fire, we see that it should have fired here, but it doesn’t because it was depolarized by the ectopic focus.

这时，如果我们测量每个窦结冲动的间隔，我们可以看到它本应在此处发放，但并没有，因为它被异位起搏点除极化了。

One important effect of the premature depolarization is that the ectopic focus will depolarize the cells of the SA node, causing the SA node to skip a cycle.

过早除极的个重要影响就是异位起搏点将会使窦结细胞除极，导致窦结跳过个心动周期。

With low levels of extracellular calcium, voltage-gated sodium channels are less stable and more likely to open up, which allows the cell to depolarize more easily, and makes the neuron more excitable.

当细胞外钙的水平较低时，电压门控钠离子通道不稳定，更容易开放，这使细胞更容易去极化，并使神经元更易兴奋。

In this case the wave of depolarization makes it into the atrium and depolarizes the atrium, including the sinus node, so essentially the sinus node resets about 4.4 boxes from the last, or 0.88 seconds.

在这种情况下，除极波进入心并使其除极，包括窦结，因此窦结被重置，离上次大约4.4小格，或0.88秒。

Remember that at rest, cells are negatively charged relative to the slightly positive outside environment and when they depolarize, the cells become positively charged, leaving a slightly negative charge in the outside environment.

要记住在静息状态下，细胞带负电，其外部环境则相对稍带正电；当它们去极化时，细胞带有正电，它的外部环境带有负电。

If the ectopic focus originates in the left ventricle, the wave will depolarizing the left ventricle first and then the right ventricle, which produces a QRS complex that looks like a right bundle branch block.

如果异位起搏点源于左心室，这个波将会首先除极左心室，然后是右心室，这会产生似于右束支阻滞的个QRS波群。

If the ectopic focus originates in the right ventricle, the wave will depolarize the right ventricle first and then the left ventricle, and this produces a QRS complex that looks like a left bundle branch block.

如果异位起搏点源于右心室，这个波将会首先除极右心室，然后是左心室，这会产生似于左束支阻滞的个QRS波群。