Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post coronary artery bypass graft surgery . The heart is mildly enlarged . There is patchy left basilar opacity which may represent pneumonia , but atelectasis and pleural effusion could also be considered . A pleural effusion is suspected but not well demonstrated . Elsewhere , the lungs appear clear . There is no pneumothorax or evidence for pleural effusion on the right .
    OUTPUT:
    
Mild cardiomegaly . No evidence of congestive heart failure . Left basilar opacification , not specific but which could be seen with atelectasis or pneumonia and probably with a pleural effusion .