Can there be a small r wave in V1 and V2 in LBBB ?
Yes .
Though we expect the reversal of septal depolarization that will extinguish the initial r in v1 to v3 . It is preserved in many. Hence the presence of small r in v1 to v3 does not rule out LBBB.
- The commonest explanation given is un-masking of RV free wall forces which is normally masked by early LV forces .
- Another possibility is the orientation of septum in pathological states.
- Third possibility is “r” may actually represent the septal q waves as in LVH or old AWMI .(Counterpart of small q in lateral leads )
Dr.S.Venkatesan MD 