Left atrial appendage closure: beyond the artifact.

Transesophageal echocardiography (TEE) represents the gold standard technique to detect left atrial appendage (LAA) thrombosis. Several conditions may be erroneously interpreted as LAA thrombus at TEE, including artifacts mimicking thrombi. We report a case of a 78-year-old man with atrial fibrillation and contraindication to anticoagulation who was referred to our institution for percutaneous left appendage closure with a transcatheter trans-septal approach. Intraoperative transesophageal echocardiography revealed a thrombus-mimicking image, related to reverberations of left upper pulmonary vein ridge, located at twice the distance of the ridge from the transducer.