What factor may increase the risk of recurrence in AVNRT after cryoablation?

The correct factor that may increase the risk of recurrence in Atrioventricular Nodal Reentrant Tachycardia (AVNRT) after cryoablation is the failure to ablate the slow pathway. In AVNRT, the arrhythmia is typically maintained by two pathways—the fast pathway and the slow pathway—within the atrioventricular node. Cryoablation is aimed at disrupting these pathways, specifically the slow pathway, which is crucial for terminating the arrhythmia effectively.

If the slow pathway is not successfully ablated, the potential for the arrhythmia to recur remains. The slow pathway is integral to the reentrant circuit of AVNRT, and its persistent functionality post-ablation can lead to re-initiation of the tachycardia. Therefore, the effective ablation of this pathway is critical for ensuring long-term success and minimizing the risk of recurrence.

The other options do not directly relate to the fundamental mechanism of AVNRT recurrence as strongly as the ablation of the slow pathway. Low freezing duration, high freezing rates, and successful cryomapping do not inherently address the need to disrupt the slow pathway effectively, which is why their influence on recurrence is less pronounced.