Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and mitral valve replacement . The heart size is normal . The mediastinal and hilar contours are within normal limits and unchanged . The pulmonary vascularity is normal . The lungs are hyperinflated . Linear band like opacity in the left lung base is compatible with atelectasis . Scarring is noted within the right upper lobe . No pleural effusion , focal consolidation or pneumothorax is present . There are mild degenerative changes in the thoracic spine .
    OUTPUT:
    
Left basilar atelectasis . No radiographic evidence for pneumonia .