Successful cryothermal ablation for Atrioventricular nodal reentry tachycardia after radiofrequency ablation failure

Background: Catheter ablation is the preferred management approach for atrioventricular nodal reentrant tachycardia (AVNRT). Cryothermal ablation (Cryo) and radiofrequency ablation (RFA) are the two clinically available ablation modalities. Atrioventricular (AV) block is a concerning potential complication and is commonly preceded by transient AV block or rapid junctional beats when using RFA. For challenging AVNRT cases, where RFA produced signs of impending AV block, we evaluate the application of Cryo to the same anatomical location where RFA was abandoned. Methods: Cryo was applied in 10 out of 313 (3.2%) total AVNRT cases from January of 2007 to June of 2010. In these cases, right-sided RFA failed in eliminating AVNRT and was aborted due to transient AV block or rapid junctional rhythm. Cryo lesions were then applied to the same anatomical location where RFA was discontinued. Patients were followed and evaluated for AVNRT recurrence. Results: Nine out of ten patients had complete elimination of AVNRT after Cryo, one of whom required a second procedure. This strategy failed in one patient, where left-sided RFA was required to eliminate AVNRT. There was one complication, tamponade, in the failed case, which was successfully managed with no long-term sequelae. There was no AV block. Conclusion: In this cohort of challenging AVNRT cases where right-sided RFA was aborted due to signs of impending AV block, applying Cryo to the same anatomical location provided procedural success, in all but one case. A prospective study is needed to accurately evaluate the safety and efficacy of this strategy.