Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided dual - chamber pacemaker is noted with leads terminating in the right atrium and right ventricle . The heart remains mildly enlarged . New ill - defined right perihilar opacity is present , concerning for an infectious process , though asymmetric pulmonary edema is also in the differential . Subsegmental atelectasis in the left lung base is present . Minimal blunting of the right costophrenic angle suggests a trace right pleural effusion . No pneumothorax is identified . There are multilevel degenerative changes in the thoracic spine .
    OUTPUT:
    
New right perihilar opacity , which could represent infection or asymmetric pulmonary edema . Trace right pleural effusion . Subsegmental atelectasis in the left lung base .