In AVNRT, what safety risk near the slow pathway should be anticipated?

• A. AV nodal injury with potential AV block
• B. Myocardial infarction
• C. Pulmonary embolism
• D. Stroke

Answer: (A)

The main concept is that the slow pathway region in AVNRT sits very close to the AV node and His-Purkinje system. When energy is delivered to ablate the slow pathway, there’s a real risk of damaging nearby nodal tissue. This can produce varying degrees of AV block, which may be temporary or require temporary or permanent pacing if conduction doesn’t recover. Because the goal is to interrupt the reentrant circuit without harming the conduction system, careful mapping, conservative energy delivery, and monitoring of AV conduction during ablation are essential.

That proximity to the AV node is what makes AV nodal injury the most likely safety risk in this setting. Myocardial infarction would involve coronary arteries and is not a typical risk of slow-pathway ablation. Pulmonary embolism and stroke are less relevant risks for this right atrial RF procedure, especially when performed with standard precautions.