Anterior border of the left atrium on conventional heart films

The appearance of the anterior left atrial wall on conventional lateral chest films is presented. The position of this structure is often marked by fatty tissue surrounding the posterior wall of the ascending aorta. A markedly enlarged left atrium may overlap the aorta. The delineation of the anterior border is still sometimes possible by observing a layer of epicardial fat surrounding the atrial wall or the interatrial sulcus. The importance of short exposure time as well as the use of the findings in practical diagnostic work is discussed.