IMPRESSION:
1.  Interval appearance of bilateral layering pleural effusions and associated
 airspace opacity which most likely reflects compressive atelectasis, although
 a pneumonia or aspiration should also be considered.  No evidence of pulmonary
 edema.  Status post median sternotomy with stable postoperative cardiac and
 mediastinal contours.  Right-sided pacer in place.  No pneumothorax.  Relative
 paucity of vasculature in the apices suggests a component of underlying
 emphysema.