71 year old male with heart palpitations.
Question 1: How do you know the premature beats are PACs?
Question 2: Why do the PACs aberrate?
-Premature atrial complexes
Question 1: Careful inspection of the T waves after each sinus beat reveals a P wave imbedded within. This is especially evident when compared with the T waves after the last 3 sinus beats.
Question 2: These beats occur relatively earlier and fall in the relative refractory period of the His-Purkinje system. This results in phase 3 block, or rate dependent aberration.