Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is mildly enlarged , but unchanged compared with prior exams . Sternotomy wires are intact . Prosthetic valve noted . Curvilinear structure overlying the anterior cardiac silhouette on lateral view could represent a calcified coronary artery . Aorta is calcified and slightly unfolded . There is mild upper zone redistribution , similar prior , without other evidence of CHF . Hilar contours are within normal limits . Likely small hiatal hernia . There is increased opacity involving the left lower lobe on lateral view which likely represents atelectasis . However , early infectious in filled should be considered in the appropriate clinical setting . Otherwise , no focal infiltrates or consolidation . No pleural effusion or pneumothorax is identified . The right hemidiaphragm is elevated similar to prior . No free air seen beneath the diaphragms .
    OUTPUT:
    
Stable cardiomegaly , status post sternotomy . Upper zone redistribution , without other evidence of CHF . Subtly increased opacity within the left lower lobe likely represents atelectasis . However , infection should be considered in the appropriate clinical setting . No other focal infiltrates and no frank consolidation . Small hiatal hernia noted .