Answer:
P waves.
Explanation:
The principal diversion is the P wave related with right and left atrial depolarization. Wave of atrial re polarization is imperceptible as a result of low sufficiency.
Typical P wave is close to 2.5 mm (two-and-a half 1-mm-divisions) tall and under 120 ms (three 1-mm-divisions) in width in any lead.