Chapter 12 Flashcards
I is isoelectric to
aVF
II is isoelectric to
aVL
III is isoelectric to
aVR
5 steps to figuring out the ventricular axis
- Find the quadrant
- Isolate the isoelectric lead
- Isolate the closest lead
- Isolate the vector
- Double-check your findings
Common causes of right axis deviation
Normal in adolescents and children RVH Left posterior hemiblock Dextrocardia Ectopic ventricular beats and rhythyms
Common causes of left axis deviation
Left anterior hemiblock
Ectopic ventricular beats and rhythms
Main criteria for RBBB
QRS prolongation of greater than or equal to 0.12 seconds
Slurred S wave in leads I and V6
RSR’ pattern in lead V1 with R’ taller than R
Incomplete RBBB
RSR’ in V1 or V2 without QRS widening
LBBB discordance
ST and T wave should be opposite the last part of the QRS (positive to negative or negative to positive) *if they are concordant it may be a sign of an underlying pathology
LBBB
Negative in V1 and V2 Positive in I V5 and V6 Greater than 0.12 seconds Broad monomorphic R waves in I and V6 Broad monomorphic S waves in V1, may have small R wave
RVH and LBBB
Typical LBBB on predcordial leads, but the frontal plane will be deviated to the right in the limb leads.
Localized IVCD
Not greater than 0.12 seconds.
Common in lead III
Somewhat like an RSR’ pattern
Universal IVCD
0.12 seconds or wider
Do not have all the characteristics of either a LBBB or RBBB.
In typical presentation, V1 has LBBB pattern and V6 has RBBB pattern.
Think hyperkalemia (deadliest cause of IVCD)
Wide QRS 4 possibilities
LBBB
RBBB
IVCD
Ventricular or aberrantly conducted beats
LBBB axis
Normal or left
