Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . Minimal linear opacities at the bases correspond with dependent atelectasis seen on concurrent chest CT . There is no pneumothorax , confluent consolidation or pleural effusion . Mediastinal and hilar contours are within normal limits . The cardiac silhouette is moderately enlarged . A prosthetic aortic valve is noted . Median sternotomy wires appear grossly intact .
    OUTPUT:
    
1 . Mild bibasilar atelectasis 2 . Moderate cardiomegaly