Before you dive into bundle branch blocks, you need to be comfortable with knowing exactly how we refer to the up and down deflections of the QRS complex.
To make your life easy, please memorize these 2 rules:
- R is up and everything else is down
- they go in alphabetical order
If there is one deflection, we only say 1 letter.
If there are 2 deflections, we way 2 letters.
If there are 3, then 3 letters.
This image summarizes all combinations you need to know:
