CONDITION AND ITS EKG FEATURESEKG Right bundle branch block QRS Duration Complete RBBB is > 0.13 sec. Incomplete RBBB is between 0.09 and 0.12 sec Morphology 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 Terminal 0.08 vector should be ignored when calculating axis Lead I = qRs. Orthogonal leads Lead X = qRS (with IRBBB = qrS) Lead Z = qRS (with CRBBB = qRs) T wave always in the opposite direction from terminal S wave Conduction abnormalities Using the usual criteria, both LAFB and LPFB can occur with RBBB Using the ususal criteria, LVH, ASMI, AMI, ACMI, and IMI can be diagnosed with RBBB.
