Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A left pacer unit projects over the left chest with leads in the right atrium and right ventricle . Post - sternotomy changes are present . The heart size is at the upper limits of normal and stable compared to prior exam . The mediastinal contours demonstrate tortuous aorta . The lungs are clear of consolidation . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
No acute cardiopulmonary process .