Rescue Pulsed-Field Ablation of Pro-Arrhythmic Multifocal Atrial Tachycardia Following Failed Conventional Ablation, A Case Report

Background: Radiofrequency ablation of right atrial appendage tachycardias remains challenging due to anatomical constraints. We present a novel case where prior ablation led to pro-arrhythmic recurrence as multifocal atrial tachycardia, successfully rescued with pulsed-field ablation. Case Presentation: A 76-year-old woman presented with incessant multifocal atrial tachycardia two months after initially successful radiofrequency ablation for focal right atrial appendage tachycardia. Repeat electro anatomical mapping revealed earliest activation along the medial free wall of the appendage. Given the complex substrate and prior ablation failure, pulsed-field ablation was employed. The arrhythmia terminated after 2applications, though frequent premature complexes persisted from the posterior free wall. Additional pulsed-field ablation applications successfully eliminated all ectopic activity. No arrhythmias were inducible post-procedure, and the patient remained arrhythmia-free at 3-month follow-up. Conclusion: Conventional right atrial appendage ablation may rarely create pro-arrhythmic substrate manifesting as multifocal tachycardia. Pulsed-field ablation, with its ability to deliver broad, deep lesions safely, represents an ideal rescue therapy for such complex recurrences. This case expands the clinical application of pulsed-field ablation beyond straightforward cases to include management of iatrogenic arrhythmias in high-risk anatomical locations.