It represents the depolarization of the atria.
Explanation:
The P wave speaks to the depolarization of the left and right chamber and furthermore relates to atrial compression. Carefully, the atria contract a brief moment after the P wave starts. Since it is so little, atrial repolarization is typically not unmistakable on ECG.
In an ordinary ECG, there's three particular waves. The primary wave is the P wave, which speaks to the depolarization of the atria. This happens directly before the atria agreement and drive blood into the ventricles. The following wave is known as the QRS wave.