Which component is targeted during AVNRT ablation?

Which component is targeted during AVNRT ablation?

• A. Slow pathway
• B. Fast pathway
• C. His bundle
• D. Right atrial appendage

Answer: (A)

AVNRT relies on a reentrant loop that uses two pathways near the AV node: a slow-conducting limb and a fast-conducting limb. In the common slow-fast form, the impulse travels antegrade down the slow pathway and returns retrograde via the fast pathway. Ablation aims to eliminate the slow pathway, disrupting the antegrade limb of the circuit and preventing reentry, which stops the tachycardia. The fast pathway can remain intact to preserve normal AV conduction, and ablation is carefully placed away from the His bundle to avoid complete AV block. The right atrial appendage isn’t part of the reentrant circuit, so it isn’t targeted.

AVNRT relies on a reentrant loop that uses two pathways near the AV node: a slow-conducting limb and a fast-conducting limb. In the common slow-fast form, the impulse travels antegrade down the slow pathway and returns retrograde via the fast pathway. Ablation aims to eliminate the slow pathway, disrupting the antegrade limb of the circuit and preventing reentry, which stops the tachycardia. The fast pathway can remain intact to preserve normal AV conduction, and ablation is carefully placed away from the His bundle to avoid complete AV block. The right atrial appendage isn’t part of the reentrant circuit, so it isn’t targeted.