Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A left - sided single lead pacemaker is seen with its tip terminating over the right ventricle in appropriate position . Heart size is mildly enlarged . The mediastinal contour is normal . There is enlargement of the right hilum . The pulmonary vasculature is normal . The lungs are hyperexpanded . Subtle opacity at the right base could represent infection . No pleural effusion or pneumothorax is seen .
    OUTPUT:
    
1 . Subtle right basal opacity could represent pneumonia . 2 . Enlargement of the right hilum may be due to reactive lymphadenopathy . Consider submitting prior images for comparison and repeat radiograph in 4 weeks to evaluate for interval change .