Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear . There are no pleural effusions or pneumothoraces . The cardiomediastinal silhouette is enlarged . The patient is status post median sternotomy . A pacer is seen with battery pack in the upper abdomen . A mitral valve replacement is seen .
    OUTPUT:
    
No evidence of acute intrathoracic process .