Which bifascicular block consists of RBBB and an anterior hemiblock?

Which bifascicular block consists of RBBB and an anterior hemiblock?

• A. RBBB + posterior hemiblock
• B. RBBB + anterior hemiblock
• C. anterior + posterior hemiblock
• D. LBBB + anterior hemiblock

Answer: (B)

The bifascicular block that consists of right bundle branch block (RBBB) and an anterior hemiblock is characterized by the combination of these two specific conduction disturbances. In this scenario, RBBB results from a blockage in the right bundle branch, which leads to a delayed depolarization of the right ventricle. The anterior hemiblock, on the other hand, refers to the failure of the anterior division of the left bundle branch to conduct impulses properly, causing issues with the anterior wall of the left ventricle.

When both of these conditions occur simultaneously, they represent a bifascicular block because they involve two of the three fascicles within the conduction system: the right bundle branch and the anterior portion of the left bundle branch. As a result of this combination, the EKG will typically display specific patterns such as a widened QRS complex due to RBBB and left axis deviation due to the anterior hemiblock.

This understanding is crucial for interpreting EKGs, as it helps differentiate between various forms of blocks and their potential implications for cardiac health. In contrast, the other choices involve different combinations of blocks that do not accurately describe the presence of both RBBB and an anterior hemiblock together.