Criteria of right bundle branch block
II. T wave is always in the opposite direction from terminal S wave.
- Complete RBBB is > 0.13 sec.
- Incomplete RBBB is between 0.09 and 0.12 sec.
- Precordial leads
- V1 = rsR' with CRBBB or V1 = rSr' with IRBBB.
- V6 = qRs with CRBBB or IRBBB
- Limb leads
- Axis can be right, left, or normal.
- Ignore terminal 0.08 vector when calculating axis.
- Lead I = qRs.
- Orthogonal leads
- Lead X = qRS (with IRBBB = qrS)
- Lead Z = qRS (with CRBBB = qRs)
III. Conduction abnormalities
- Both LAFB and LPFB can occur with RBBB using usual criteria.
- LVH, ASMI, AMI, ACMI, and IMI can all be diagnosed with RBBB using usual criteria.
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