Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A left pectoral pacemaker is in place . The chin and overlying soft tissues partially obscures lung apices . There is no obvious pneumothorax . Aside from minimal left basilar subsegmental atelectasis , the lungs are clear . A rounded left infrahilar contour is new , and may be due to left hilar adenopathy , an enlarged left atrium , or a new descending aortic aneurysm . A small left pleural effusion and left basilar subsegmental atelectasis have decreased .
    OUTPUT:
    
Rounded left infrahilar contour may be due to new adenopathy , an enlarged left atrium , or a descending thoracic aortic aneurysm . A contrast - enhanced chest CT is recommended for further evaluation . Decreased small left pleural effusion and left basilar subsegmental atelectasis .