Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are mildly hypoinflated with persistent left lower lobe atelectasis and small left pleural effusion . Chronic left atrial contour abnormality is noted . Heart size , mediastinal contour , and hila are otherwise unremarkable .
    OUTPUT:
    
Persistent left lower lobe atelectasis and small left pleural effusion .