Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Median sternotomy wires are in place . Heart size is normal . The mediastinal silhouette and hilar contours are normal . There is mild retrocardiac atelectasis . Lungs are otherwise clear . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
No acute cardiopulmonary abnormality .