EKG - Rhythm

The next thing to look at is the RHYTHM of the EKG.  Most of the EKG’s that you will come across will be in sinus rhythm and will be driven by the sinus (SA) node.  On an EKG, this will be evidenced by a P wave preceding every single QRS complex.  Additionally, the P waves should all look the same since they are all being generated from the same point of origin, the SA node.  They should also all have the same PR interval.  Discussion of the other rhythms is more complicated and can be discussed later when looking at specific EKG’s that are not generated by the SA node.

Source: https://kchemekg.wordpress.com/ekg-test-home/