Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is increased opacity at right lung base which could be due to atelectasis , however pneumonia is possible in correct clinical setting . There is mild pulmonary edema . Mildly enlarged cardiomediastinal silhouette is similar to prior . Large hiatal hernia is again noted . Left pectoral pacemaker leads terminate at the right ventricle and right atrium .
    OUTPUT:
    
Increased opacity at right lung base could be due to atelectasis , however pneumonia can not be ruled out .