Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest provided . Midline sternotomy wires , prosthetic cardiac valve and mediastinal clips are again noted . A retrocardiac opacity is compatible with known hiatal hernia . Faint linear density in the left lower lung is likely atelectasis . No focal consolidation , large effusion or pneumothorax is seen . Cardiomediastinal silhouette appears normal . Bony structures are intact .
    OUTPUT:
    
Hiatal hernia , otherwise unremarkable .