Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Again seen is a left - sided pacemaker device , with one lead coursing through a left - sided SVC terminating in the right atrium , and a second lead terminating in the right ventricle , coursing through the right - sided SVC . The heart size is moderately enlarged , and the aorta remains mildly tortuous . There is new left basilar opacity with adjacent small to moderate sized left pleural effusion , new from the prior study . Right lung remains clear , and there is no pneumothorax . There is no pulmonary vascular congestion . No acute osseous abnormalities are seen .
    OUTPUT:
    
New left basilar opacification , possibly representing atelectasis , though infection can not be excluded , with new small to moderate sized left pleural effusion .