Background <p>Approximately one-fifth of patients undergoing pulmonary vein isolation have a left common ostium (LCO). These patients tend to have worse arrhythmia-free survival when treated with a single-shot device, which may be related to lesion location and ablation thermodynamics.</p> Purpose <p>This study evaluates lesion characteristics around the LCO in paroxysmal atrial fibrillation (AF) patients treated with a pentaspline pulsed-field ablation (PFA) modality.</p> Methods <p>Twenty-two patients underwent PFA. Directly after the PFA applications, an electro-anatomical map (EAM) was created using the PFA catheter. After the procedure, three experienced operators were asked to draw a fictional ideal ablation line in the EAM encompassing the LCO. Outcome measurements were operators’ satisfaction with the lesion characteristics and the distance from the lesion to the fictional ablation line.</p> Results <p>The median age was 61 years [56–73] and the median CHA₂DS₂-VA was 1.0 [0.0–2.0]. Based on the EAM, the majority of the operators (≥ 2/3) considered unintended ablation at the mitral isthmus or posterior wall in 9 patients (40.9%), would perform additional ablation at the LCO in 11 patients (50.0%), and had no remarks in 6 patients (27.3%). The distance (lesion – fictional ablation line) at the left atrium roof was 3.6&#xa0;mm [-4.8–11.2], mid posterior wall 3.3&#xa0;mm [-2.6–8.9] and inferior --1.7&#xa0;mm [-7.9–2.7].</p> Conclusions <p>The LCO lesion location after PFA in paroxysmal AF patients varies widely compared to the ideal ablation line. According to three experienced operators, unintended ablation and/or electrical activity were present in a substantial group of patients.</p> Graphical Abstract <p></p>