Non-obstructive membranes of the left atrial appendage.

The left atrial appendage (LAA) is a blind-ending, complex structure distinct from the body of the left atrium and is sometimes regarded as a minor extension of the atrium. However, it should routinely be analysed as part of a transoesophageal echocardiographic examination. In this study we describe the presence of a non-obstructive membrane traversing the cavity of the LAA, found incidentally on transoesophageal echocardiography.