ECG changes in left bundle branch block (LBBB)
Last reviewed 01/2018
ECG findings:
- there is a Q in V1 and an R wave in V6 - there is depolarization of the right ventricle before the left. Thus despite the smaller muscle mass of the right ventricle, there is also an R in V1 and an S in V6. These changes may only appear as notches on the ECG.
- subsequent depolarisation causes an S in V1 and another R in V6.
Left bundle branch block is best seen in V6 where there is an M pattern. An M pattern may also be seen in I and AVL.
ECG changes in bundle branch block
Sgarbossa criteria for diagnosis of myocardial infarction (MI) in left bundle branch block (LBBB)