Pulsed Field Ablation for Perimitral Atrial Flutter With Involvement of the Vein of Marshall: A Case Report

BACKGROUND: Perimitral atrial flutter (PMF) involving the vein of Marshall (VOM) remains a therapeutic challenge. The role of pulsed field ablation (PFA) in the treatment of PMF is unclear. CASE PRESENTATION: A 65-year-old male was admitted with a 7-year history of palpitations. He had undergone three previous radiofrequency ablation procedures for atrial fibrillation and atrial flutter (AFL). He was readmitted due to recurrent AFL, with an electrocardiogram indicating atypical AFL. A three-dimensional electrophysiological activation map of the left atrium revealed a macro-reentrant circuit consistent with clockwise PMF. This was characterized by gaps in color isochrones and a total mapped activation time that was shorter than the tachycardia cycle length. The earliest activation was observed at the CS 5-6 electrodes, where a distinct double atrial potential was also recorded. These findings suggested an epicardial connection from the VOM to the circuit. PFA using the VARIPULSE PFA was successfully used to terminate the AFL at the VOM's endocardial insertion site into the left atrium. CONCLUSION: In our case, PFA appears to be a safe and effective strategy for targeting the endocardial insertion site of the VOM for VOM-mediated PMF.