Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A pacer unit projects over the left chest with leads in the right atrium , right ventricle , and coronary sinus . The heart size is at the upper limits of normal . The mediastinal contours show no widening . The lungs are clear , although the volumes are somewhat low . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
No acute cardiopulmonary abnormality .