Atrioventricular Blocks

    Back

    64 year old male with syncope.

    64 year old male with syncope.

    Questions

    Question 1: Where in the conduction system does the first PAC fail to conduct?

    Question 2: Why does one of the PACs conduct while two PACs do not?

    Key Findings

    -Sinus rhythm-Premature atrial contractions (intermittently blocked)

    Coding for Boards

    -Sinus rhythm

    -Atrial premature complexes

    -AV block, 1st degree

    -LVH

    Answers

    Question 1: AV Node.

    Question 2: The conducted PAC falls outside of the refractory period of the AV node. The blocked PACs fall within the refractory period of the AV node.