Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP and lateral views of the chest are compared to previous exam from ___ . Dense retrocardiac opacity with air - fluid level is compatible with hiatal hernia as previously seen . The lungs are otherwise grossly clear based on this exam which has poor inspiratory effort . There is no pleural effusion . Cardiomediastinal silhouette is otherwise unremarkable as are the osseous structures .
    OUTPUT:
    
No definite acute cardiopulmonary process given an exam with low inspiratory effort . Large retrocardiac hiatal hernia .