Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided pacemaker device is seen with unchanged lead position . The lungs appear well expanded and clear . No focal consolidation , pleural effusion , or pneumothorax is seen aside from retrocardiac atelectasis . The heart is normal in size with normal cardiomediastinal contours .
    OUTPUT:
    
No acute intrathoracic process .