Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A pacer unit projects in the left upper chest with leads in the right atrium and right ventricle . Post - CABG changes are present . The cardiomediastinal contours are unchanged compared to prior exam . The lungs are clear . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
1 . No acute cardiopulmonary process .