Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided pacemaker / AICD device with single lead terminating in the right ventricle is unchanged . Moderate to severe enlargement of cardiac silhouette is re - demonstrated . There are marked aortic knob calcifications . Lung volumes are low . This causes crowding of the bronchovascular structures . Patchy opacities in the lung bases likely reflect atelectasis . No focal consolidation , pleural effusion or pneumothorax is demonstrated . There are no displaced fractures seen .
    OUTPUT:
    
Low lung volumes with mild bibasilar atelectasis .