Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes . Unchanged mild cardiomegaly . Unchanged left chest defibrillator with electrodes in expected positions . The mediastinal and hilar contours are unchanged . The pulmonary vasculature is normal . Lungs are clear . No pleural effusion or pneumothorax is seen .
    OUTPUT:
    
No acute cardiopulmonary abnormality .