The P wave represents the spread of the electrical impulse through the atria, and this is referred to as atrial depolarization.

P波代表电脉冲通过心房的传播，这被称为心房去极化。

On an electrocardiogram or ECG which measures the electrical activity of the heart via electrodes that are placed on the skin, the atrial depolarization, and therefore its contraction, is seen as a p-wave.

在通过置于皮肤的电极测量心脏电活动的心电图上，心房去极化，即心房收缩，显示为P波。