Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided AICD / pacemaker device is re - demonstrated with leads terminating in the right atrium and right ventricle . The patient is status post median sternotomy and CABG . Mild to moderate cardiomegaly is re - demonstrated . The mediastinal and hilar contours are unchanged . Low lung volumes causes crowding of the bronchovascular structures without overt pulmonary edema . Patchy opacities in the lung bases likely reflect atelectasis . There is no pleural effusion or pneumothorax . Clips are demonstrated within the upper abdomen on the lateral view .
    OUTPUT:
    
Mild bibasilar atelectasis .