Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A left - sided dual chamber pacemaker is in unchanged position , with leads terminating in the right atrium and right ventricle . Pulmonary arteries are enlarged . There is mild calcification of the aortic arch . Mild streaky opacities in the right upper lung are likely related to prior radiation changes . No new focal consolidation is identified . No pneumothorax or pulmonary edema present .
    OUTPUT:
    
Left - sided dual chamber pacemaker is in unchanged position . No pneumothorax .