Bundle-Branch-Blocks

(Circ 2009;119:e235)

參考 ➡️ AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part III: intraventricular conduction disturbances: a scientific …

Normal

Initial depol. left to right across septum (r in V1 & q in V6; nb, absent in LBBB) followed by LV & RV free wall, with LV dominating (nb, RV depol. later and visible in RBBB).

RBBB

1. QRS ≥120 msec (110-119 msec = IVCD or “incomplete”)
2. rSR′ in R precordial leads (V1, V2)
3. Wide S wave in I and V6
4. ± ST↓ or TWI in R precordial leads

LBBB

1. QRS ≥120 msec (110-119 msec = IVCD or “incomplete”)
2. Broad, slurred, monophasic R in I, aVL, V5-V6 (± RS in V5-V6 if cardiomegaly)
3. Absence of Q in I, V5, and V6 (may have narrow q in aVL)
4. Displacement of ST & Tw opposite major QRS deflection
5. ± PRWP, LAD, Qw’s in inferior leads