Transcatheter Ethanol Ablation of Recurrent Right Atrial Appendage Diverticulum‐Related Atrial Tachycardia in a Child

BACKGROUND: Focal atrial tachycardia (AT) originating from a right atrial appendage (RAA) diverticulum is rare in children and often poses significant challenges for conventional radiofrequency catheter ablation (RFCA) due to limited catheter access and poor tissue contact. We report the successful use of transcatheter 95% ethanol chemical ablation as a bailout strategy in a child with recurrent AT and suspected arrhythmia-induced cardiomyopathy (AIC). CASE PRESENTATION: A 10-year-5-month-old boy with a history of incessant AT and severe left ventricular dysfunction (LVEF 23%) was diagnosed with suspected AIC. Although initial RFCA successfully terminated the tachycardia, AT recurred 2.5 months later. Repeat electrophysiological study with high-density mapping localized the earliest activation to the RAA roof. Intraprocedural right atrial angiography revealed a transversely oriented diverticulum-like sac arising from the RAA roof, communicating with the prior ablation site and preventing stable catheter engagement. Transcatheter chemical ablation was performed using an ST Blue ablation catheter positioned at the ostium of the diverticulum-like structure. After confirmation of selective contrast opacification without extravasation, a test bolus of 1 mL 95% ethanol was infused, resulting in immediate termination of the AT. A total of approximately 10 mL ethanol was delivered incrementally. Consolidation radiofrequency applications were then performed at the ostium to electrically isolate the ablated region. The procedure was uneventful, with no complications. Post-procedural monitoring confirmed non-inducibility of AT, and the patient remained arrhythmia-free at short-term follow-up with stable left ventricular function. CONCLUSION: This case demonstrates the feasibility and efficacy of bailout transcatheter ethanol ablation for recurrent AT arising from an inaccessible RAA diverticulum-like structure in a pediatric patient with AIC. Intraprocedural angiography was crucial for identifying the anatomical substrate. Ethanol chemical ablation may serve as a safe and effective alternative when conventional catheter ablation fails due to complex anatomy.