Which test is used to uncover an accessory pathway if AVRT ablation is not successful?

• A. Adenosine given to uncover AP if not successfully ablated
• B. Vagal maneuvers
• C. Beta-blockers
• D. Exercise stress test

Answer: (A)

Unmasking a remaining accessory pathway after AVRT ablation failures is what this item focuses on. Adenosine briefly blocks AV nodal conduction. If, after the AV node is paused, the atrial impulse can still travel to the ventricles via the accessory pathway, you’ll see conduction through that pathway become evident—often as renewed pre-excitation on the ECG or by affecting the tachycardia in a way that indicates the AP is still capable of conduction. This makes adenosine a useful diagnostic tool to confirm the presence and activity of an accessory pathway when ablation hasn’t eliminated it, guiding further attempts at ablation.

Vagal maneuvers slow the AV node and can terminate AVNRT or AVRT that relies on the AV node, but they don’t specifically reveal whether an accessory pathway remains. Beta-blockers also slow AV nodal conduction and can alter tachycardia, but they aren’t used as a targeted test to uncover AP conduction. An exercise stress test isn’t a focused method to reveal or map an accessory pathway.