Where is slow-pathway modification usually targeted in AVNRT?

• A. Posteroseptal region near Koch's triangle within the AV nodal region
• B. Anterosuperior region near the superior vena cava
• C. Lateral right atrial wall
• D. Left atrial appendage

Answer: (A)

In AVNRT the slow pathway lies in the posteroseptal region of the AV nodal area, near Koch’s triangle. Targeting this area for ablation modifies or eliminates conduction through the slow pathway, which stops the reentrant circuit while aiming to preserve the fast pathway and AV node function. That’s why the posteroseptal region just inferior and posterior to the AV node is the usual site for slow-pathway modification.

Other regions don’t fit the typical anatomy of the slow pathway. The anterosuperior region near the SVC is more associated with the fast pathway, and the lateral right atrial wall or left atrial appendage are not part of the AVNRT circuit.