Introduction <p>Pulsed field ablation (PFA) has emerged as a promising energy modality for atrial and ventricular ablation. There is limited data on the feasibility of PFA in the coronary venous system. This study evaluated the feasibility of PFA delivery in the coronary venous system of a swine model.</p> Methods <p>Bipolar biphasic PFA was applied in branches of the coronary venous system, using a linear multielectrode catheter which is commercially available for coronary venous mapping – The EPStar Fixed Electrophysiology Catheter (Baylis). PFA lesions were assessed by changes in local electrograms and gross pathology.</p> Results <p>Five swine were included. Energy was successfully delivered using adjacent electrodes on a linear multielectrode catheter positioned in coronary venous tributaries. PFA delivery was associated with discernible acute depolarization and repolarization changes in local electrograms. Local electrogram attenuation was observed at 26/30 (87%) of PFA delivery sites. In electrodes remote from the delivery site, isolated repolarization changes were seen in 25/32 (78%) PFA deliveries, and concomitant depolarization and repolarization changes were seen in 15/32 (47%) PFA deliveries. After ablation, gross examination of the coronary sinus and its tributaries revealed discrete myocardial lesions at targeted sites. The lesions demonstrated a characteristic appearance, with a central hemorrhagic core surrounded by a pale, well-demarcated rim. This pattern was consistent across animals and ablation sites.</p> Conclusion <p>This initial experience suggests that PFA in the coronary venous system is feasible, using a linear multielectrode catheter which is commercially available for coronary venous mapping. Experiments for optimization of PFA delivery in the coronary venous system and characterization of chronic ablation lesions are ongoing.</p>