Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post sternotomy and repair of ascending aorta . There is similar marked enlargement of both the left atrial appendage and main pulmonary artery , accounting for enlarged lobular left upper cardiac borders . The lower part of the chest is partly excluded , making it difficult to exclude very small effusions but there is some degree of retrocardiac opacification suggested on the frontal view only .
    OUTPUT:
    
Possible retrocardiac opacification , although without correlate on the lateral view , perhaps an artifact . If there is persistent concern for an evolving pulmonary process , repeat radiographs showing the entirety of the lung bases could be considered in short - term follow - up .