ECG Level 2 Tutorial: Origins of Activity
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Tutorial: Origins of Activity
This module will teach how to determine the origins (pacemaker location) of the electrical activity.
How to level up?
Develop your skills by completing our Practice Cases!
Tutorial: Origins of Activity The 4 Options
Times Practiced
Cases Completed
1h 24m
Total Time spent
1m 24s
Average Time
The 4 Options
There are 4 options where the electrical activity can start in the heart:
  1. Sino-atrial (SA) node
  2. Atria
  3. Atrio-ventricular (AV) node
  4. Ventricles

We can determine the origin of the P wave and also the origin of the QRS. Usually, there is only 1 origin of electrical activity and it produces both the P wave and the QRS. However, sometimes there are 2 origins of electrical activity and one produces the P wave and the other produces the QRS. You will understand how and why this occurs in better detail after you finish the next module on diagnostic criteria.

If this lesson seems too easy so far, please be patient; the concepts will get more difficult. In fact, determining the origin(s) of the electrical activity is probably the most difficult step of analysing the ECG ... so be patient if you feel like you are struggling. Practice will make it easier.

On to the rules ...