Dilatation of the Left Atrial Appendage

Dilatation confined to the appendage of the left atrium is an unusual condition. There appear to be two varieties, one group occurring with an intact pericardium and the other in association with a pericardial defect. Only 8 examples have been reported, of which 7 were submitted to thoraco- tomy. Of these one was described as a diverticulum of the left atrium (Pitts and Potts, 1962), but in many respects it was similar to the cases that are the subject of this paper and is, therefore, included. The one that was not treated surgically was proven by angiography but the state of the pericardium was not known.