Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided pacemaker device is noted with leads terminating in the right atrium and right ventricle , unchanged . Moderate cardiomegaly is re - demonstrated . There are low lung volumes which result in bronchovascular crowding . No overt pulmonary edema is identified . Retrocardiac opacity may reflect atelectasis but infection can not be excluded . No definite large pleural effusion or pneumothorax is identified . There are no acute osseous abnormalities .
    OUTPUT:
    
Low lung volumes with probable retrocardiac atelectasis , although infection can not be excluded in the correct clinical setting . No pulmonary edema .