Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Battery pack seen in overlying the left lung base , with lead extending superiorly apparently represents a left - sided vagus nerve stimulator , based on prior chest x-ray report . A Port - A - Cath type right subclavian central line is present , tip over proximal most SVC . It s tip appears to lie slightly more proximal 1 on the prior film . No pneumothorax is detected . Heart size is prominent , but not frankly enlarged . There is upper zone redistribution , without overt CHF , similar to prior . Allowing for obscuration of the left lung base , no focal infiltrate or gross effusion is identified .
    OUTPUT:
    
The Port - A - Cath tip lies slightly more proximal on today 's exam . Otherwise , I doubt significant interval change . No acute pulmonary process is identified .