Bundle Branch Blocks Flashcards
Anatomy—> Bundle of Hiss splits into…
L and R bundles, L bundle —> anterior and posterior fascicles
Left axis deviation
-30 Q4 = left anterior fascicular block
Right axis deviation
> 120 —> RVH (big R in V1) if no evidence of RVH then left posterior fascicular block
90-120 is RVH
Right bundle branch block
Bunny ears in V1
Fatta essa
Left bundle branch block
Big QRS
S4
Stiff LV
HOCM
stenosis
Ischemia
S1 loud
Mitral stenosis, short PR
S1 soft
Mitral regurg, Long PR
S1 variable
A fib
Heart block (complete)
VT
Fixed split S2
ASD
Physiologic split S2
A2 P2
I I inspiration
I I expiration
RBBB exaggerated splitting —>
I I insp
I I exp
LBBB paradoxical splitting —>
P2 A2
II insp
I I exp
MV prolapse
Mid systolic click,
Earlier w/ abrupt standing
Later w/ squatting
Narrow QRS
Problem above the bundle
Wide QRS (>3 boxes)
Prob below the bundle
How do you know if an LAFB is 2/2 inferior MI?
No Rs in II, III, avF
Method to ID LAFB
1) Look at the axis, < -30
2) Look at II, III,avF —> Rs=anatomical LAFB, Qs=IMI (can have Rs and Qs)
Method to ID LPFB
1) axis >120
2) look at V1 —> if R is normal it’s LPFB
Method to ID RBBB
1) V1 bunny ears (little R, big R)
2) I, avL, V6 (lat leads) fatta essa
subtract last 0.04s of QRS to read axis
Can have nl axis, right dev (120) = bifascicular + LPFB, L dev (-30) = bifascicular + LAFB
Reversed rabbit ears
Ventricular beat, MI
Method to ID LBBB
1) QRS>3 boxes
2) V1 Q
3) I, avL, V6 NO Qs
*axis can be nl, L or R
Looking for MI w/ a LBBB
QRS and ST-T waves should be OPPOSITE
Concordance is already weird w a LBBB, look for even small 1mm ST elev
Discordance, need bigger ST elev > 25% S
If you have an LBBB w/ Qs in the lateral leads I, avL
It’s a SEPTAL (not high lateral) infarct!
If you have a LBBB w notched Qs in V2,3,4
Old infarct, non-localizing (Cabrera sign)
