A “rate-dependent” right bundle branch block can also occur during times of fast heart rate. When the heart rate slows, the narrow QRS complex returns.

AFib with aberrancy means there is a problem with the heart conduction system, such as a bundle branch block. The left and right bundle branches help conduct signals to the ventricles.

(RTTNews) - Abbott (ABT) announced the successful completion of the world's first in-human leadless left bundle branch area pacing procedures using the company's investigational AVEIR Conduction ...