Left atrial appendage occlusion device-related thrombus: a case report and review of the literature

A 75-year-old male with persistent atrial fibrillation underwent implantation of a left atrial occlusion device. After 6 weeks, a scheduled trans-esophageal echocardiogram showed a 1.1-cm × 1.1-cm mass within the occluded left atrial appendage, suspected to be thrombus. He was continued on warfarin for an additional 6 weeks and a repeat trans-esophageal echocardiogram showed obliteration of the left atrial appendage. This report describes an uncommon observation detected at scheduled follow up by trans-esophageal echocardiogram, which sheds some light on the mechanism by which this device "matures" after it is implanted inside the left atrial appendage.