Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is at the upper limits of normal size . The left upper superior contour of the heart is mildly prominent which may suggest enlargement of the left atrial appendage . The possibility of left atrial enlargement is also suggested by the lateral view , where the heart closely approaches the spine posteriorly . The lungs appear clear . There are no pleural effusions or pneumothorax . Mild degenerative changes are noted along the thoracic spine .
    OUTPUT:
    
Borderline cardiomegaly with suggestion of possible left atrial enlargement , but no evidence of acute disease .