Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A single portable AP chest radiograph was obtained . Aeration of the left base has minimally improved since the prior exam two days ago . A left basilar retrocardiac opacity continues to obscure the left hemidiaphragm . No new consolidation , effusion , or pneumothorax is present . Soft tissue density surrounding a left chest pacer corresponds with the clinically noted pacer pocket hematoma . A single cardiac lead projects over the right ventricle . Cardiomegaly remains mild . The aortic arch and mitral valve anulus are calcified .
    OUTPUT:
    
1 . Minimal improvement in left basilar aeration . Persistant left lower lobe opacity can represent both atelectasis or pneumonia ; this differentiation can not be made on this exam . 2 . Left chest soft tissue density corresponds with known pacer pocket hematoma .