Additional Diagnostic value of Mini Electrodes in an 8-mm Tip in Cavotricuspid Isthmus Ablation

Background: Eight-mm ablation catheters are widely used in cavotricuspid isthmus ablation (CTI) for treatment of right sided atrial flutter. However a high success rate, these large ablation tips comes with adisadvantage of lower resolution of fractionated signals. Purpose: The aim of this study was to evaluate the additional diagnostic value of the electrograms recordedfrom mini electrodes (MEs) in an 8-mm ablation catheter tip during CTI. Methods: CTI-ablation procedures were compared retrospectively in two groups, namely, group A: the Abbott Safire 8-mm tip with a 3D mapping system (n =37) and group B: the Boston Scientific MiFi IntellaTip XP 8-mm tip without a 3D mapping system (n=13). We analyzedacute procedural success, ablation characteristics and recurrence rate at one-year follow-up. Electrograms from MEs were analyzedright before the onset of the critical ablation application that resulted in acute CTI-block. We determined whether these ME electrograms had additional diagnostic value in addition to of the 8-mm tip derivedelectrogram. Results: At the onset of the critical ablation application, the MEs had an important additional value in 3 out of 13 cases as local signals were sensed on the MEs that were not recorded by the 8-mm tip electrode. In 2cases the ME did not show local electrogramsalthough the ablationwas still effective. Acute procedural and long-term success wereobserved in all patients. No differences were found in time to bidirectional block, procedure time or fluoroscopic exposure. Conclusion: Our data show that signals recorded from the MEs had additional diagnostic value, but only in asmall percentage of the patients. We did not observe, although omitting 3D-mapping in the ME group, any differencebetween groups with regard to procedural or ablation characteristicsduring CTI-ablation.