Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy . The heart size is mildly enlarged , increased in size compared to the previous study . Mediastinal and hilar contours are unremarkable . There is no pulmonary edema . Minimal atelectasis is noted at the lung bases . No pleural effusion or pneumothorax is present . There are no acute osseous abnormalities .
    OUTPUT:
    
Mild bibasilar atelectasis . Slightly enlarged heart size compared to the previous exam .