Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided pacemaker device is noted with leads in unchanged positions in the right atrium and right ventricle . Moderate cardiomegaly is similar compared to the prior radiograph . The mediastinal contour is unchanged . Lungs are hyperinflated compatible with underlying emphysema . Prominence of the hilar contours unchanged with mild pulmonary vascular congestion , as seen previously . Patchy airspace opacities are noted in the left lung base , more pronounced than on the previous study , and may reflect early infection . No large pleural effusion or pneumothorax is seen . There are no acute osseous abnormalities . Mild degenerative changes are present in the thoracic spine .
    OUTPUT:
    
Patchy airspace opacities in the left lung base may reflect atelectasis but infection is not excluded . Mild pulmonary vascular congestion .