Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph obtained . Overlying EKG leads are present . The lungs appear clear aside from mild basal atelectasis . No definite signs of pneumonia or CHF . Cardiomediastinal silhouette is normal . Bony structures are intact .
    OUTPUT:
    
Mild lower lung atelectasis . Otherwise normal .