Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are moderately well expanded . Hazy opacity in the left lung base is similar to prior and likely represents known chronic atelectasis . The lungs are otherwise clear . There is no pleural effusion or pneumothorax . The cardiomediastinal silhouette is enlarged . A pacer is seen overlying the right anterior chest with intact leads in appropriate position .
    OUTPUT:
    
No acute cardiopulmonary process . Little change from prior .