We illustrate pulmonary vein anatomy in 2 patients undergoing multi-slice computed tomography (MSCT) scanning prior to atrial fibrillation ablation, including anomaly of the pulmonary vein. The anomalous variations need to be investigated before catheter procedure, because of the anomalous variations. Non-invasive imaging using MSCT could have important clinical implications and provide the physicians useful information on morphological feature in patients with atrial fibrillation before catheter ablation.