Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Again noted is a left - sided pacemaker device with one lead coursing through a left - sided SVC and terminating in the right atrium , a second lead terminating in the right ventricle , coursing through the right - sided SVC . The heart size is moderately enlarged . The aorta is tortuous . There is again noted is left basilar opacity . The right lung remains clear , although there is minimal blunting of the right costophrenic angle which may suggest trace right pleural effusion . There is no pneumothorax .
    OUTPUT:
    
Left pleural effusion , slightly smaller , with probably underling atelectasis ; however , underlying infectious process can not be completely excluded in the correct clinical setting .