During cryoablation, an AV ratio of 1:4-1:10 is acceptable.

• A. True
• B. False
• C. Depends on patient size
• D. Only with specific catheter

Answer: (B)

The atrial-to-ventricular (A:V) ratio is a measure of how large the atrial and ventricular components of the local electrogram are at the ablation site. There is no fixed, universally accepted target like 1:4 to 1:10 for cryoablation. The correct approach is to localize the target tissue using precise mapping and electrophysiological cues (such as the presence or absence of His-bundle potentials and conduction responses during pacing), and to use cryomapping and careful energy delivery to avoid injury to critical conduction tissue. A fixed ratio would not reliably indicate a safe or effective site, so the claim is not correct.