Which of the following is the preferred definitive treatment for atrioventricular nodal reentrant tachycardia (AVNRT)?

• A. Catheter ablation of the slow AV nodal pathway
• B. Beta-blocker therapy
• C. Catheter ablation of the fast AV nodal pathway
• D. Electrical cardioversion

Answer: (A)

AVNRT is a reentrant tachycardia that uses two conducting pathways in or near the AV node—a slow pathway for antegrade conduction and a fast pathway for retrograde conduction. The definitive way to cure the arrhythmia is to disrupt this reentrant circuit by selectively ablating the slow AV nodal pathway. This eliminates the pathway that sustains the loop without unnecessarily compromising the fast pathway, giving a high chance of long-term freedom from tachycardia while preserving overall AV conduction.

Beta-blocker therapy can control symptoms but does not remove the substrate for recurrence. Electrical cardioversion terminates an acute episode but does not prevent future episodes. Ablation of the fast AV nodal pathway is a possible alternative in some cases, but it carries a higher risk of causing AV block because of its proximity to the His bundle, making it less favorable as the first-line definitive treatment.