Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There has been interval placement of a pacer unit over the left chest with leads terminating in the expected areas of the right atrium and the right ventricle . There is no pneumothorax . The heart size continues to be enlarged . The mediastinal contours demonstrate a tortuous aorta and prominent pulmonary arterial hump . The lungs are clear of consolidation . There is no pleural effusion .
    OUTPUT:
    
Status post pacer units placement with leads as described above , and stable cardiomegaly .