Unveiling an Unusual Cause of Cardiac Tamponade.

This case presents a 48-year-old woman initially diagnosed with an ostium secundum atrial septal defect (ASD) at the age of 36. Twelve years post-intervention, she presented to the emergency department with cardiac tamponade. This case highlights the importance of maintaining prolonged follow-up for individuals undergoing percutaneous ASD closure, given the possibility of potentially fatal late complications of ASD occlusion devices.