Is the left atrial appendage more than a simple appendage?

The left atrial appendage (LAA) is a cardiac structure with unique anatomic and functional features. It is significantly more than a simple chamber appended to the left atrium (LA), differing from the LA in structure, function, and hormonal activity. Unfortunately, it is the source of more than 90% of cardiac-based emboli, particularly in atrial fibrillation, mandating lifelong anticoagulation. Percutaneous LAA exclusion was developed to limit or eliminate cardioembolic events in patients with atrial fibrillation. Benign healing of the appendage occurs without adverse hemodynamic effects, and with no residual surface thrombus or tissue damage. The feasibility of this treatment is now established, suggesting that percutaneous therapy is safe, practical and possibly effective to eliminate the need for anticoagulation and significantly reduce cardioembolic events. (c) 2009 Wiley-Liss, Inc.