During RF ablation of AVNRT, the appearance of junctional beats suggests that ablation is affecting the slow pathway.

• A. True
• B. False
• C. Not related
• D. Requires mapping

Answer: (A)

Junctional beats during RF ablation for AVNRT indicate that the energy is hitting tissue near the AV node, where the slow pathway fibers reside. The slow pathway runs close to the AV nodal tissue, and when ablation irritates or modifies this region, the AV node can take over as the pacemaker momentarily, producing a junctional rhythm with QRS complexes that are usually narrow. This pattern is a reassuring sign that the ablation is affecting the tissue responsible for the slow pathway and aiming to disrupt the reentrant circuit. Therefore, seeing junctional beats is consistent with successful slow-pathway modification.