Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A Swan - Ganz catheter terminates in the right pulmonary artery and is in adequate position . The heart is substantially enlarged but unchanged . The mediastinal and hilar contours are normal . There is a left basal opacity , minimally increased from prior study which likely represents atelectasis . There is no evidence of hemothorax or mediastinal widening . No pleural effusion or pneumothorax is identified .
    OUTPUT:
    
1 . Increased left basal opacity , which likely represents atelectasis . 2 . Swan - Ganz catheter in appropriate position .