Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Status post left pectoral dual - chamber pacemaker with leads in the right atrium and right ventricle . Blunting of the left costophrenic angle likely due to atelectasis rather than effusion . No pneumothorax . No focal consolidation . Cardiac size is top normal . Mediastinal contours unchanged . Median sternotomy wires again noted .
    OUTPUT:
    
Pacer leads in expected positions . No pneumothorax . Left lower base atelectasis .