E1: Axis And Chamber Enlargement Flashcards
What leads do you look at to determine axis?
What is considered a normal axis with these leads?
Leads 1 and aVF
If the predominant direction is positive in non of these leads, the axis is normal
The mean QRS axis is normally between what degrees?
Between 0 and +90
If there is left axis deviation, the axis is between what degrees?
0 and -90
If there is RAD, the axis is between what degrees?
+90 and +180
What does it mean if lead 1 is negative and aVF is positive?
RAD
What does it mean if lead 1 is positive and aVF is negative?
LAD
What does it mean if both lead 1 and aVF are negative?
Indeterminate axis
What is a vertical heart?
Tall and thin individuals may have a more vertical heart, with a shift in the QRS axis toward +90
What is a horizontal heart?
Obese or pregnant individuals may have a more horizontal heart with a mean QRS axis shifting more leftward
What leads are used to assess for atrial enlargement?
Leads II and V1
What P wave finding is suggestive of RAE?
P wave amplitude >2.5mm
What P wave finding is suggestive of LAE?
P wave duration >0.10 seconds
How can you assess for RAE using V1 where the P wave is biphasic?
The initial component of the P wave in V1 is larger than the terminal component
What 2 conditions are common with RAE?
Pulmonic stenosis, tricuspid stenosis, and Tricuspid regurgitation
How can you assess for LAE using V1 where the P wave is biphasic?
The terminal portion of the P wave in V1 is negative with a duration of ≥0.04 seconds and a depth of >1mm
