Pericardial tamponade occurred 3 days after the catheter closure of an atrial septal defect (ASD) using Amplatzer Septal Occluder (St. Jude Medical, St. Paul, MN, USA). Before the closure, two-dimensional and real-time three-dimensional transesophageal echocardiography demonstrated a deficient aortic rim and atrial septal malalignment. Perforation of the right atrium toward the non-coronary sinus of the aortic root was confirmed at the emergent surgery. Cardiac erosion is one of the most catastrophic complications in ASD patients undergoing catheter closure with Amplatzer Septal Occluder. Hence, several risk factors for this complication are discussed and identified. Oversized device deployment and a deficient aortic rim are accepted factors potentially causing cardiac erosion. Besides, atrial septal malalignment, which is a morphological characteristic of ASD, may be a novel risk factor for cardiac erosion. <Learning objective: Cardiac erosion is a potentially lethal complication when catheter closure of atrial septal defects using Amplatzer Septal Occluder (St. Jude Medical, St. Paul, MN, USA) is provided to the patients. However, mechanisms of this complication remain to be completely elucidated. Atrial septal malalignment may be one of the novel risk factors for this catastrophic complication.>.