ECG Bundle Branch Block Flashcards
what happens to cause BBB?
one of the left/right bundle branches is not conducting normally
which leads are used to determine BBB?
V1 and V6
which leads show electrical activity in
RV
IVS
LV?
RV - V1 and 2
IVS - V3 and 4
LV - V5 and 6
what does the bundle of his divide into?
Right bundle branch
Left bundle branch -> left posterior hemibundle and left anterior hemibundle
what is the QRS like in BBB?
broad (>0.12s)
what is diagnostic of partial/incomplete BBB?
pattern of LBBB/RBBB but QRS is not >0.12s
how does activation in the bundle branch occur?
septum depolarises from left to right
depolarisation of the ventricles occurs at the same time
what happens in RBBB?
right ventricle stimulated by an impulse from the left, instead of being stimulated together
ECG changes in RBBB?
M in V1
W in V6
(williaM morroW -> reading from RHS)
ECG criteria for RBBB?
QRS >0.12s
rSR complex in V1
delayed S wave in V4, V5 and V6 (slurred)
what should you consider in a new diagnosis of LBBB?
MI
what happens in LBBB?
left ventricle stimulated by an impulse from the right, instead of being stimulated together
how can LBBB occur?
injury to both the left anterior and posterior hemibundles
ECG changes in LBBB?
W in V1
M in V6
(William Morrow -> reading from LHS)
ECG criteria for LBBB?
QRS >0.12s
M in I, aVL, V5 and V6
r wave in V2 and V3
