ECG - LAFB/LPFB

LAFB, a.k.a: L. ant. hemiblock:

• QRS 90 - 100 msec or normal

• Left axis deviation (r/o other causes - COPD, inf. MI, LVH) more neg than -45 degrees

• rS complexes in II, III, aVF

• q wave in I and/or aVL

LPFB, a.k.a - L. post. hemiblock:

• RAD (r/o other causes: RVH, COPD, lat. MI, RBBB). Axis >110 degrees

• narrow QRS <120 msec

• rS wave in I, aVL

• Leads II, III, aVF:

  • narrow QRS

  • qR wave

• Pattern: rS in I, aVL; qR in II III, aVF.