Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The frontal and lateral chest radiograph demonstrates stable cardiomediastinal silhouette with mild prominence of the left atrium . Pacemaker leads are well positioned . The lungs are clear . No pleural effusion or pneumothorax identified . Multilevel degenerative changes are present . Sternotomy sutures are midline and intact .
    OUTPUT:
    
No acute intrathoracic process .