Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The position of the single lead right - sided pacemaker is unchanged and following the standard course . The midline tracheostomy tube is unchanged . There is an increased opacification of the left base for pneumonia in patient with chronic left base atelectasis . Right base scarring / atelectasis is stable There is no pneumothorax or pleural effusion . The cardiomediastinal silhouette and hilar contours are unchanged
    OUTPUT:
    
Left base pneumonia .