Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The Swan - Ganz catheter tip is seen slightly more advanced in the main pulmonary artery but still in the borders of the mediastinum . The lungs are clear . The left pacemaker is unchanged . Heart size is moderately enlarged . No pneumothorax or pulmonary edema .
    OUTPUT:
    
The Swan - Ganz catheter tip is seen slightly advanced but likely still within the main pulmonary artery .