Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographs again demonstrate a left chest wall pacer device with leads overlying the right atrium and ventricle , as well as median sternotomy wires and clips along the left heart border . The heart remains enlarged . The thoracic aorta is tortuous and dilated , similar in caliber compared to ___ . Lung volumes are low with patchy retrocardiac opacity , likely atelectasis . No appreciable pleural effusion or pneumothorax is visualized .
    OUTPUT:
    
Previously noted mild pulmonary edema appears improved . Patchy retrocardiac opacity , likely atelectasis .