Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is dense opacity in the left lung base which could be due to combination of large left pleural effusion and left lower lobe volume loss . Superimposed pneumonia is also possible . Cardiac silhouette is obscured by large left pleural effusion , however probably moderately enlarged . Faint opacity at the right lung base is likely atelectasis . Left pectoral pacemaker with 2 leads terminating in right ventricle and right atrium are in unchanged position .
    OUTPUT:
    
Dense opacity in the left lung base could be due to left lower lobe volume loss and large left pleural effusion . Superimposed pneumonia is also possible .