Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy and CABG . Heart size remains mildly enlarged . The mediastinal and hilar contours are unchanged . There is crowding of the bronchovascular structures due to low lung volumes without overt pulmonary edema . Patchy opacities in lung bases likely reflect atelectasis . No pleural effusion or pneumothorax is present . There are no acute osseous abnormalities . Electronic device is again noted within the left upper chest wall .
    OUTPUT:
    
Low lung volumes with bibasilar atelectasis .