Hemiblock Flashcards
1
Q
What is a hemiblock?
A
A defect in conduction along one of the two hemifasicles of the left bundle branch
(thus, there are 2 types - LAHB and LPHB)
2
Q
Which type of hemiblock is the most common?
A
LAHB (by far)
3
Q
ECG changes for LAHB?
A
- left axis deviation (frontal plane QRS axis <30 degrees)
- initial R waves in the inferior leads
- part of trifasicular block when associated with RBBB and 1st degree heart block
4
Q
why is LPHB rare?
A
because the left posterior hemifasicles has dual blood supply from LAD and PDRCA
- damage to the blood supply will usually lead to LBBB
5
Q
ECG changes in LPHB?
A
- right axis deviation (frontal plane QRS axis of 90-180)
- S1 Q3 pattern
- normal or slightly prolonged QRS
6
Q
what is an S1 Q3 pattern (ass with LPHB)
A
who knows
