Introduction: Pulsed field ablation (PFA) is being increasingly studied for catheter ablation of atrial arrhythmias. However, there is little published on the efficacy of ventricular PFA. Recently, a 7.5-Fr ablation catheter with a 9mm compressible lattice-tip linked to a magnetic electroanatomical mapping system has been introduced (Sphere-9 and HexaMap, Prism-1, respectively; Affera, Inc). In contrast to radiofrequency ablation, there is little understating how to create an adequate lesion depth on the myocardial using PFA. Accordingly, we assessed the feasibility and effectiveness of repetitive PFA pulses in creating ventricular lesions using the lattice-tip catheter in porcine preclinical studies. Methods: Under general anesthesia, low dose 1-sec PFA pulses were delivered in 4 healthy swine ventricles using lattice-tip catheter and its compatible PF generators (HexaPulse, Affera, Inc). Three strategies were assessed: 2, 3 or 4 applications at each location. Pulses were repeated at 10-15 sec intervals. After survival for ~ 24 hrs, swine were sacrificed humanely, and TTC staining was performed to ascertain lesion dimensions on gross pathology. Results: Discrete PFA lesions (n=51) were successfully delivered: 24 in the RV and 27 in the LV. Dimensions were obtained for 49 of 51 discrete lesions. Transmurality was observed in 9 of 23 (39%) RV and 1 of 26 (4%) LV lesions. Significantly larger ventricular lesions were noted with the 4-application strategy: length 17.6±3.9 mm, width 13.4±1.8 mm and depth 6.1±2.1 mm (see Figure ). The myocardium was trabeculated at 40 of 49 lesion locations: all lesions projected uniformly into the tissue without surface gaps. No sustained ventricular arrhythmias were observed during PFA. Conclusion: Focal PFA using a lattice-tip ablation catheter revealed clinically-relevant ventricular lesions without complications; repetitive applications significantly increase lesion dimensions.