Cardiac Axis
Cardiac Axis
Look at leads I, II, aVF
Look at leads I, II, aVF
Leads I, II, aVF "look" in the direction of the normal vector (down to the left)
Since the leads look in the direction of the vector... the inflection should be positive (most of the QRS going up)
Normal Cardiac Axis
Normal Cardiac Axis
The net directional movement of electricity is toward the LV (normally)
When things (ischemia, hypertrophy) affect conductivity... the vector can change
Left Axis Deviation
Left Axis Deviation
Lead II differentiates pathologic from physiologic LAD
(Isoelectric in lead II = physiologic)
Right Axis Deviation
Right Axis Deviation
Extreme Right Axis Deviation
Extreme Right Axis Deviation
Play with the Cardiac Axis Trainer
Thumb Rule
Thumb Rule
Your left thumb = Lead I
Your left thumb = Lead I
Your right thumb = Lead aVf
Your right thumb = Lead aVf
Two thumbs up = Normal
Left thumb up and Right thumb down = LAD
Left thumb down and R thumb up = RAD
Both thumbs down = extreme RAD