Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided pacemaker device is noted with leads terminating in the right atrium and right ventricle . The heart size is mildly enlarged but unchanged . The mediastinal and hilar contours are stable . There is no pulmonary edema . Streaky opacities in the lung bases likely reflect atelectasis . Fracture of the left posterior 6th rib is better demonstrated on the shoulder radiographs obtained the same day . Degenerative changes are noted within the thoracic spine .
    OUTPUT:
    
Bibasilar atelectasis . Left posterior ___ rib fracture is better demonstrated on the shoulder radiographs obtained the same day .