ECG - RBBB
QRS duration >120 msec = complete
Normal or RAD
Leads V1 and V2, or V3R
Wide QRS with classic triphasic rSR' ("M" or "rabbit ears" pattern), delayed IDT (intrinsicoid deflection time):
initial r wave missing in concomitant antero-septal MI, replaced by QS wave.
deep slurred S wave
Terminal tall R' wave
ST segment depression and T wave inversion directed opposite to the RSR' pattern in the respective leads.
Any time RBBB has an initial R in V1 equal to or greater than the R', true posterior MI must be considered