Insight of Focal Atrial Tachycardia From Right Atrial Appendage in a Case of Resistant to Catheter Ablation: Immunohistological Assessment of the Excised Specimen.

INTRODUCTION

Atrial tachycardias originating from right atrial appendages (RAA-AT) are often refractory to catheter ablation (CA). The extent of the localization of arrhythmogenic foci has been described.

METHODS AND

RESULTS

A 25-year-old male with RAA-AT experienced recurrence after CA and subsequently underwent right atrial appendectomy. Analysis of the excised specimen, including immunostaining, identified a region enriched with hyperpolarization-activated cyclic nucleotide-gated channel 4 but lacking connexin 43. The findings suggest that the presence of sinoatrial-like cells at the site of origin contributed to atrial tachycardia recurrence.

CONCLUSION

Our case provided the arrhythmogenic entity of RAA-ATs, which elucidated the difficulty of CA.