RBBB

Right bundle-branch block, see there.

bundle branch block

BBB

A defect in the electrical conduction system of the heart in which there is failure of conduction down one of the main branches of the bundle of His. On the surface electrocardiogram, the QRS complex is > 0.12 sec. and its shape is altered. Synonym: bundle branch heart block; interventricularheart block

left bundle branch block

Abbreviation: LBBB
A defect in the conduction system of the heart in which electrical conduction down the left bundle branch is delayed. On the 12-lead EKG, it gives the QRS complex a widened QS complex in lead V₁ (0.12 sec.).

right bundle branch block

Abbreviation: RBBB
A defect in the conductive system of the heart in which electrical conduction down the right bundle branch is delayed. On the 12-lead EKG, it gives the widened QRS complex an RSR appearance in leads V₁ and V₂.