During cryo ablation for AVNRT, what is typically observed?

During cryo ablation for AVNRT, what is typically observed?

• A. Immediate AV block
• B. Ablate during NSR only
• C. No effect during tachycardia
• D. Ablate during tachycardia and watch for slow then termination

Answer: (D)

In cryoablation for AVNRT, the key idea is to test and confirm the slow pathway contribution while the tachycardia is running, using a reversible, cryomapping approach. You apply the cold energy during the tachycardia and look for a change in the arrhythmia. The typical observation is that conduction through the slow pathway slows and the tachycardia eventually terminates. If the effect is favorable, you can proceed to create a permanent lesion; if not, you can rewarm and move to a different site. This approach reduces the risk of permanent AV block because you’re able to observe the tachycardia response before committing to a full lesion. Immediate AV block is not the expected initial finding, and ablation during NSR alone typically won’t reveal the critical slow-pathway involvement. The hallmark is slow conduction followed by termination during tachycardia.

In cryoablation for AVNRT, the key idea is to test and confirm the slow pathway contribution while the tachycardia is running, using a reversible, cryomapping approach. You apply the cold energy during the tachycardia and look for a change in the arrhythmia. The typical observation is that conduction through the slow pathway slows and the tachycardia eventually terminates. If the effect is favorable, you can proceed to create a permanent lesion; if not, you can rewarm and move to a different site. This approach reduces the risk of permanent AV block because you’re able to observe the tachycardia response before committing to a full lesion. Immediate AV block is not the expected initial finding, and ablation during NSR alone typically won’t reveal the critical slow-pathway involvement. The hallmark is slow conduction followed by termination during tachycardia.