Phospholamban p.arg14del Mutation in a Spanish Family With Arrhythmogenic Cardiomyopathy: Evidence for a European Founder Mutation

the slow pathway (recurrence rate of 9.5%) were compared with the 41 patients with residual conduction through the slow pathway with a single echo beat (recurrence rate of 14.6%, P = .4). The other variables analyzed were not associated with a higher recurrence rate. The main findings in this series of patients with nodal reentrant tachycardia treated with cryoablation with an 8-mm catheter are as follows: a) we confirmed that the initial efficacy in an adult population is very high, with similar success rates to those obtained with radiofrequency ablation; b) the safety profile was excellent, even with 8-mm catheters, which do not allow cryomapping; c) our results suggest that the recurrence rate during the first year can be reduced by extending the duration of initially successful application to 8 minutes; d) modification of the slow pathway was not found to be important, as failure to detect anterograde conduction was not associated with better clinical outcome than residual conduction inducing a single echo beat. The most controversial aspect of cryoablation is the higher recurrence rate associated with this technique compared with radiofrequency (10% vs 4%, respectively). There is a lack of comparative studies, but the recurrence rates in the published series with 8-mm catheters of around 5% are lower than those reported with cryoablation with 4and 6-mm catheters and are similar to those reported with radiofrequency ablation. These results may have been influenced by the conditions in which cryoablation was applied. For example, Chan et al, who reported a relapse rate of 5.6%, performed a security freeze in the same area as the successful application, and Peyrol et al, who reported a recurrence rate of 4.9%, also mention that they performed an additional application of 4 minutes at the site of successful application. Bearing in mind that tissue adherence is lost during periods of heating and thus precision may be lost, we decided to simply extend the duration of cryoapplications from 4 minutes to 8 minutes in our patients. If low recurrence rates were to be confirmed in larger prospective series when applications are extended to 8 minutes, this catheter and application method could improve the outcomes of treatment of nodal reentrant tachycardia with cryoablation.