Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided dual - chamber pacemaker is noted with leads terminating in the right atrium and right ventricle , unchanged . Mild cardiomegaly is again noted , with diffuse calcification and tortuosity of the thoracic aorta . The mediastinal and hilar contours are otherwise unchanged . There is minimal prominence of the pulmonary vascular markings , suggestive of mild congestion , but no overt pulmonary edema is seen . Subtle patchy opacities in the lung bases may reflect atelectasis . No pleural effusion or pneumothorax is present . There are no acute osseous abnormalities .
    OUTPUT:
    
Bibasilar atelectasis . Possible mild pulmonary vascular prominence , but no overt pulmonary edema .