## LBBB vs IVCD ± LVH

- Used to distinguish true LBBB from other causes of LBBB-like pattern, such as LVH, LAFB + LVH. Patients with true LBBB may have greater benefit from cardiac resynchronization therapy.

## Criteria

- QRS duration ≥ 140 msec men or ≥ 130 msec women
- QS or rS in leads V1 and V2
- mid-QRS notching or slurring in ≥ 2 leads V1, V2, V5, V6, I, aVL
- All 3 criteria must be met to diagnose true LBBB

## Reference

- Strauss DG, Selvester RH, Wagner GS. Defining Left Bundle Branch Block in the Era of Cardiac Resynchronization Therapy. American Journal of Cardiology. 2011;107(6):927-934. https://doi.org/10.1016/j.amjcard.2010.11.010