Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Tracheostomy is in place . A left - sided pacemaker with leads terminating in the right atrium and right ventricle is noted . A right - sided PICC line is present with its tip terminating in the mid to distal SVC . A presumed shunt catheter is seen traversing the right neck , chest and upper abdomen . Sternotomy wires and valvuloplasty are noted . A retrocardiac opacity unchanged and likely represents persistent left lower lobe collapse . Patchy atelectasis at the right lung base appears improved since prior study . There is no pleural effusion or pneumothorax . The heart size is unchanged and normal . The mediastinal silhouette is unremarkable .
    OUTPUT:
    
Persistent left lower lobe collapse with mild improvement in the previously seen bibasilar atelectasis , however , infection can not be fully excluded .