Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A right - sided subclavian central venous catheter is present , terminating at the cavoatrial junction . A left - sided subclavian central venous catheter is present , terminating in the lower SVC . The cardiac mediastinal silhouettes appear unchanged in within normal limits . There is slightly increased opacity seen in the left base in the retrocardiac region , likely representing atelectasis , without a definite consolidative process . Overall lung markings appear slightly increased when compared to the prior examination , although very similar in appearance is when compared to the examination from 2 days previous . This is likely due to differences in penetration .
    OUTPUT:
    
Overall , no appreciable interval change over the last few days . Left retrocardiac atelectasis appears slightly worse than the prior examination , but essentially unchanged when compared to the examination from ___