Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were obtained . The heart is of normal size . Prominent retrocardiac opacity suggests left atrial enlargement . The aorta is unfolded , similar to prior . Lungs are clear . No focal consolidation , pleural effusion , or pneumothorax . No radiopaque foreign body .
    OUTPUT:
    
Prominent retrocardiac opacity , suggesting left atrial enlargement . No focal consolidation .