Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Sternotomy wires and mediastinal clips are unchanged as is the prosthetic aortic valve . The heart size is within normal limits . The mediastinal contours appear unremarkable . There continues to be opacity projecting over the heart on the frontal view with air bronchograms which correlates with increased opacity in the retrocardiac space . There is no pneumothorax .
    OUTPUT:
    
Left lower lobe pneumonia .