Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided pacemaker device with leads terminating in the right atrium and right ventricle is again noted . Heart size is normal . Aortic knob is mildly calcified . Mediastinal and hilar contours are unchanged . Upper lobe predominant emphysema is again noted . Streaky bibasilar airspace opacities likely reflect atelectasis . No pleural effusion , pulmonary vascular congestion , or pneumothorax is identified . There are mild degenerative changes in the thoracic spine .
    OUTPUT:
    
Emphysema . Mild bibasilar atelectasis .