Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral radiographs were obtained of the chest . The lungs appear clear aside from mild left - sided atelectasis due to large hiatal hernia as on previous examination . No pleural effusion or pneumothorax is seen . The heart is obscured by the hiatal hernia . Mediastinal and hilar contours are otherwise unremarkable .
    OUTPUT:
    
No acute intrathoracic process with a large hiatal hernia causing mild left basilar atelectasis .