Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy and CABG . Left - sided pacemaker device is noted with leads terminating in the right atrium and right ventricle . Mild cardiomegaly is re - demonstrated . Aortic knob calcifications are present . Mediastinal contour is unremarkable . Low lung volumes cause crowding of the bronchovascular structures . There may be mild pulmonary vascular congestion without overt pulmonary edema . Linear opacities in the lung bases likely reflect areas of atelectasis . No focal consolidation , pleural effusion or pneumothorax is present . Moderate degenerative changes are seen in the thoracic spine .
    OUTPUT:
    
Low lung volumes with bibasilar atelectasis and possible mild pulmonary vascular congestion .