Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph provided without comparison . A pacer device overlying the left axilla with leads extending into the region of the right atrium and right ventricle noted . Retrocardiac opacity could represent atelectasis or pneumonia . There is a small right pleural effusion . Mild pulmonary vascular congestion is present . There is no pneumothorax . The imaged bony structures are intact .
    OUTPUT:
    
1 . Retrocardiac opacity concerning for atelectasis or pneumonia . Small right pleural effusion . 2 . Mild pulmonary interstitial edema .