Why might RBB injury be a concern in LBBAP?

RBB (Right Bundle Branch) injury is a concern in LBBAP (Left Bundle Branch Area Pacing) primarily because it poses a greater risk when there is an existing full LBBB (Left Bundle Branch Block). This is due to the fact that both the left and right bundle branches are critical components of the heart's conduction system, and damage to the right bundle branch can exacerbate existing conduction issues related to the left bundle.

When RBB injury occurs in conjunction with a full LBBB, there is a loss of effective electrical conduction to both sides of the ventricles. This situation can lead to more severe bradycardia or heart block than if only one bundle branch was affected. Additionally, a patient who already has LBBB may not have optimal heart function, and adding RBB injury creates cumulative risks that can lead to worsening heart failure or more complicated pacing scenarios, illustrating the heightened seriousness of RBB injury in this context.

In summary, the concern with RBB injury in patients with existing LBBB is the potential for combined conduction disturbances, which could result in significant clinical implications, including impaired heart function and challenges in management.