Mitral isthmus ablation with pulsed field ablation technology through an epicardial approach with the CENTAURI system.

Mitral isthmus (MI) ablation is an essential part of persistent atrial fibrillation (AF) ablation, particularly in redo procedures where pulmonary vein isolation (PVI) is durable, but AF recurs. While radiofrequency (RF) ablation is commonly used, creating a complete MI line can be challenging and associated with significant risks. Pulsed field ablation (PFA) offers a safer alternative, providing tissue selectivity with fewer complications. This case report explores a hybrid endocardial and epicardial approach for PFA of mitral isthmus. Specifically, a 64-year-old woman with recurrent AF underwent a redo-ablation after two prior PVI procedures performed with RF. Electroanatomical mapping of the left atrium was performed using the INTELLAMAP ORION mini-basket catheter (Boston Scientific, Marlborough, MA, USA). Mitral isthmus ablation was attempted with a linear contact force catheter connected to the CENTAURI PFA generator (CardioFocus, Inc., Marlborough, MA, USA). Initial endocardial PFA failed to achieve bidirectional block of the mitral isthmus. Additional RF bursts were deployed to injure Marshall bundle autonomic component since PFA alone is known to be ineffective in achieving nerve damage. The ablation catheter was then advanced into the coronary sinus for epicardial mapping, where a gap in the isthmus was identified. PFA delivered through the epicardium successfully achieved bidirectional block with no complications. Hybrid Learning objective: Mitral isthmus (MI) block in addition to pulmonary vein isolation ablation could be required for treatment of patients with persistent atrial fibrillation and high post-ablation recurrence rates. MI ablation with pulsed field ablation (PFA) technology can address challenges in traditional radiofrequency ablation, particularly in complex redo procedures. PFA based on a hybrid