Which statement correctly distinguishes Cryo from RF ablation for AVNRT?

• A. Cryo allows test of ablation effect during tachycardia with gradual termination; RF requires ablation in NSR with slow junctional beats
• B. Cryo always causes AV block
• C. RF cannot treat AVNRT
• D. Cryo only used for diagnostic mapping

Answer: (A)

The main idea is how each ablation energy source interacts with tissue during AVNRT ablation. Cryo ablation allows a test freeze (cryomapping) to assess the effect while tachycardia is ongoing, and the effect often develops gradually as the tissue cools. If the test shows the desired change, you can proceed; if not, you can rewarm and adjust sites without committing to a permanent lesion. This reversible testing during tachycardia is a safety and planning advantage of cryo.

Radiofrequency ablation, on the other hand, creates permanent lesions as energy is delivered, and the practical approach is to perform ablation during sinus rhythm with observation for effects, including the appearance of slow junctional beats when near the AV node. Those junctional rhythms serve as a procedural marker during RF ablation of the slow pathway in AVNRT.

So the statement captures the key distinction: cryo lets you test the effect during tachycardia with gradual termination during a cryo “test,” whereas RF ablation is typically performed in normal rhythm with slow junctional beats as a sign of proximity to the AV node. It’s not true that cryo always causes AV block, RF cannot treat AVNRT, or that cryo is only for mapping.