Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral radiographs of the chest demonstrate substantial right - sided pleural effusion with displacement atelectasis of the right lower lobe . Possible right middle lobe atelectasis as well . Cardiomediastinal and hilar contours are unchanged . There is moderate cardiomegaly . Transvenous aorto - biventricular pacer leads are in unchanged position .
    OUTPUT:
    
Substantial right pleural effusion with displacement atelectasis of the right lower lobe and possible right middle lobe atelectasis as well .