Not just another large atrial septal defect: complex anatomy, challenging procedure, and an unusual complication.

We report the case of a 59-year-old patient with a complex atrial septal defect in whom a 40-mm Amplatzer™ septal occluder was surgically extracted 50 days following implantation. Deployment manoeuvres were challenging leading to an immediate pericardial effusion that was closely monitored and uneventfully drained after 11 days. A dry pericardium was documented until 4 weeks of outpatient routine follow-up. However, the device was surgically explanted 2 weeks later, when an urgent chest computed tomography performed for worrisome symptoms showed pericardial effusion recurrence with peripheral contrast enhancement. Surprisingly, the surgical view showed a well-positioned device and an intact pericardium. We discuss the atypical sequence of clinical findings misleading our clinical judgement and precipitating surgery.