Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared to the prior film , inspiratory volumes are slightly lower . As before , the patient is status post sternotomy there is possible mild cardiomegaly , though this is likely accentuated by low inspiratory volumes and portable AP technique . There is upper zone redistribution , without overt CHF . There is slight increase in hazy retrocardiac opacity , consistent with early left lower lobe collapse and / or consolidation . Otherwise , no focal opacity identified . No effusion . No pneumothorax detected .
    OUTPUT:
    
Equivocal mild cardiomegaly . Mild upper zone redistribution . Slight increase in faint retrocardiac opacity , consistent with atelectasis . An early left lower lobe infectious infiltrate is considered less likely but can not be entirely excluded .