Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a small left pleural effusion , with underlying collpase and / or consolidation which is largely unchanged from ___ in keeping with Dressler 's syndrome . There is a small amount of pleural fluid and / or thickening along the left chest wall and at the left apex . Platelike atelectasis is seen throughout the left midzone . The right lung is clear . There is no pneumothorax . The cardiac and mediastinal contours are normal with persistent sslight hift of the mediastinum to the left . Aortic valve and sternotomy wires are constant . Mild hyperinflation , suggesting background COPD .
    OUTPUT:
    
Left mid-zone atelectasis is new . Otherwise , no significant change . Small left effusion is essentially unchanged .