Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided dual - chamber pacemaker device is noted with leads terminating in the right atrium and right ventricle . Heart size is mildly enlarged . Mediastinal and hilar contours are unchanged , with diffuse calcification of the aorta re - demonstrated . The pulmonary vascularity is normal . Linear opacities in both lung bases likely reflect atelectasis . There is no focal consolidation , pleural effusion or pneumothorax . Multilevel degenerative changes are noted in the thoracic spine . Remote fracture of the right 7th rib is re - demonstrated .
    OUTPUT:
    
Mild bibasilar atelectasis .