EKG P Wave Definition, duration, shape P Wave Definition The P wave represents atrial depolarization. In a normal EKG, the P-wave precedes the QRS complex. It looks like a small bump upwards from the baseline. The amplitude is normally 0.05 to 0.25mV (0.5 to 2.5 small boxes). Normal duration is 0.06-0.11 seconds (1.5 to 2.75 small boxes). The shape of a P-wave is usually smooth and rounded. P-wave questions:Are they present?Do they occur regularly?Is there one P-wave for each QRS complex?Are the P-Waves smooth, rounded, and upright?Do all P-Waves have similar shapes?