Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single frontal view of the chest was obtained . The patient is status post median sternotomy . There has been mediastinum and cardiac valve replacement . The cardiac silhouette remains enlarged . There is mild bibasilar atelectasis . Evidence of old rib fractures is seen bilaterally . The previously seen small bilateral pleural effusions have likely decreased in size .
    OUTPUT:
    
No acute cardiopulmonary process .