Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph was provided . Lung volumes are low . The heart remains moderately enlarged . There is retrocardiac opacity , likely atelectasis . Small right pleural effusion is likely present . There is no overt edema . No pneumothorax . Bony structures intact .
    OUTPUT:
    
Stable cardiomegaly with probable atelectasis in the left lung base and tiny right pleural effusion .