Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single frontal view of the chest was obtained . A left pleural effusion with overlying atelectasis remains present . Left base retrocardiac opacity likely represents combination of atelectasis and effusion , although underlying consolidation is difficult to exclude . Patient is status post median sternotomy and CABG . No definite focal consolidation is seen in the right lung . The patient is status post median sternotomy and cardiac valve replacement . Cardiac and mediastinal silhouettes are stable .
    OUTPUT:
    
Left pleural effusion with overlying atelectasis , underlying consolidation is difficult to exclude .