Focal pulsed field ablation for atrial tachycardia near the phrenic nerve: a two-case experience

BACKGROUND: Catheter ablation of atrial tachycardia (AT) adjacent to the phrenic nerve is limited by the risk of diaphragmatic injury with conventional energy sources. Pulsed field ablation (PFA) is a non-thermal modality with relative tissue selectivity that may reduce collateral damage. We describe two patients with symptomatic AT arising from the crista terminalis in close proximity to the phrenic nerve who underwent ablation with a novel focal PFA catheter (TactiFlex Duo, Abbott). Case 1: A 76-year-old man with recurrent AT after incomplete prior ablation received 12 focal PFA applications at the mid-crista terminalis. Phrenic nerve capture was preserved throughout, and sinus rhythm was restored without complication. Case 2: A 25-year-old woman with symptomatic supraventricular tachycardia underwent 12 low-energy PFA lesions at the posterolateral right atrium. Transient phrenic nerve palsy occurred but fully recovered by the end of the procedure. In both cases, durable sinus rhythm was achieved without long term phrenic injury. CONCLUSION: Focal PFA enabled acute termination of crista terminalis AT in close proximity to the right phrenic nerve, including one case with preserved phrenic capture throughout and one case with reproducible transient phrenic nerve palsy after each application with full recovery. These cases support the feasibility of focal PFA in phrenic-adjacent right atrial substrates, while underscoring that phrenic nerve stunning can occur.