Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Inspiratory volumes are slightly low . Again seen is left - sided pacemaker , with lead tips over the right atrium and right ventricle . A small left effusion is present , progressed compared with the prior study . As before , the left hemidiaphragm is tented laterally . Possible mild cardiomegaly , similar to the prior study . There is slight upper zone redistribution , but no overt CHF . Slight increased retrocardiac density is unchanged and could reflect left lower lobe atelectasis . Otherwise , no focal opacities . No obvious right pleural effusion . No pneumothorax is detected .
    OUTPUT:
    
1 . New or increased small left pleural effusion . 2 . Upper zone redistribution , without other evidence of CHF or volume overload . 3 . Mild cardiomegaly , unchanged . 4 . Mild atelectasis left lower lobe , unchanged .