Left juxtaposed atrial appendages: diagnostic two-dimensional echocardiographic features.

Left juxtaposition of the atrial appendages is usually associated with cyanotic congenital heart disease. Recognition of this rare anomaly is important before therapeutic or surgical procedures that involve the atrial septum can be undertaken (for example, septostomy, the Mustard or Senning operation and the Fontan anastomosis). The diagnosis of left juxtaposition of the atrial appendages is most commonly an incidental finding at the time of surgery or autopsy. This report describes the two-dimensional echocardiographic visualization of left juxtaposed atrial appendages. The diagnostic echocardiographic features are based on characteristic alterations of the plane of the atrial septum and visualization of the malpositioned right atrial appendage. On the basis of these observations, a noninvasive diagnosis of left juxtaposed atrial appendages is now possible by means of two-dimensional echocardiography.