What type of block results from delayed depolarization in the right or left bundle branch?

What type of block results from delayed depolarization in the right or left bundle branch?

• A. Atrial fibrillation
• B. Bundle branch block
• C. AV node block
• D. Sinoatrial block

Answer: (B)

Bundle branch block occurs when there is a delay or obstruction in the electrical conduction pathways of the right or left bundle branches of the heart. Each bundle branch runs along the interventricular septum and carries electrical impulses to the respective ventricles.

When any bundle branch is blocked, the timing of depolarization in the ventricles becomes impaired, leading to abnormal QRS complexes on the EKG. A right bundle branch block is characterized by a widened QRS complex and specific patterns in the lead V1, while a left bundle branch block presents different features, such as a broader complex and changes in the leads reflecting the left ventricle. This condition is distinctly different from other types of heart blocks, such as AV node or sinoatrial block, which affect the conduction at different points in the heart's electrical system.

Understanding bundle branch block is crucial for EKG interpretation, as it can indicate underlying cardiac conditions and may require further evaluation to assess the heart's overall function.