Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded and clear . The cardiomediastinal silhouette , hilar contours and pleural surfaces are normal . No pleural effusion or pneumothorax is present . A left - sided pacer terminates with its tip in the right atrium , right ventricle , and coronary sinus . A replaced mitral valve is noted .
    OUTPUT:
    
No acute intrathoracic process .