Transesophageal echocardiographic finding of left atrial appendage lobe mimicking a mass lesion.

We describe an elderly patient undergoing ablation for atrial fibrillation in whom, two-dimensional transesophageal echocardiography showed a mass-like lesion in or adjacent to left atrial appendage (LAA). This mass-like effect was produced by en face visualization of the top of a LAA lobe in the presence of a small effusion in the transverse sinus of the pericardium.