Which leads should be examined on an EKG if a bundle branch block is suspected?

Which leads should be examined on an EKG if a bundle branch block is suspected?

• A. Leads I and II
• B. Leads V1 and V2
• C. Leads V3 and V4
• D. Leads III and aVF

Answer: (B)

When examining for a bundle branch block on an EKG, leads V1 and V2 are particularly important. These leads provide essential information about the electrical conduction of the heart from the right ventricle and through the interventricular septum. In the case of a right bundle branch block, the characteristic "rabbit ear" appearance is often seen in lead V1, where there is an RSR' pattern. Similarly, lead V2 can show the delayed depolarization that occurs due to the block.

The importance of these leads stems from their specific positioning directly over the ventricles. Understanding the changes in these leads helps in identifying the direction and presence of blocks in the bundle branches. Therefore, when assessing for a bundle branch block, focusing on V1 and V2 is crucial for accurate interpretation.