Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest film ___ at 16 :08 is submitted
    OUTPUT:
    
Left - sided pacer remains in place . Overall , the right hemidiaphragm remains elevated and lung volumes are low with patchy bibasilar opacities likely reflecting atelectasis . Heart remains enlarged status post median sternotomy with an aortic valve replacement . No evidence of pulmonary edema . No pneumothorax . Old left - sided healed rib fractures .