Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a dual - lead pacemaker / ICD device with leads again terminating in the right atrium and ventricle , respectively . The cardiac , mediastinal and hilar contours are probably unchanged . Superimposed on background volume loss and band - like opacity in the posterior left lower lobe is increased volume loss and hazy opacity superimposed upon prior findings at the left lung base . A trace pleural effusion is also difficult to exclude on the left but not definitely present . Elsewhere , the lungs remain clear .
    OUTPUT:
    
Increased volume loss in opacity at the left lung base . Whether this may represent developing pneumonia or worsening atelectasis superimposed on chronic scarring is uncertain and should be correlated with clinical findings .