Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is no evidence of pneumothorax or pneumonia . Cardiomegaly is mild but stable . The lungs are well aerated . A right chest generator is connected to a single pacing lead . Mitral valve prosthesis is present . No obvious fractures . Patient is status post median sternotomy .
    OUTPUT:
    
No evidence of acute cardiopulmonary process .