Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral chest radiograph demonstrates low lung volumes . Patient is status post median sternotomy . When compared to prior radiograph dated ___ , there is been no significant changes . The heart is enlarged . There is no evidence of overt pulmonary edema . There is no pleural effusion or pneumothorax . No acute osseous abnormality is detected .
    OUTPUT:
    
Stable cardiomegaly . Low lung volumes . No acute intrathoracic abnormality .