What can an RN do that a LPN Cannot?

Reflects electrical impulse beginning at the SA node
Reflects atrial muscle depolarization
Has duration of normally 0.11 seconds or less.

In a client who has had an ECG, the P wave represents the activation of the electrical impulse in the SA node, which is then transmitted to the AV node. In addition, the P wave represents atrial muscle depolarization, not ventricular depolarization. The normal duration of the P wave is 0.11 seconds or less in duration and 2.5 mm or more in height.