Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A left pectoral pacemaker is unchanged in position or appearance from the most recent prior study , with a single lead terminating in the right ventricle , unchanged . The lungs are symmetrically well expanded and well aerated without focal airspace opacity , pleural effusion or pneumothorax . The pulmonary vasculature is not engorged . The cardiac silhouette is top normal in size , but stable . The mediastinal and hilar contours are within normal limits . The trachea is midline . There are healed right posterior lower rib fractures but no acute displaced rib fractures . There is no free air beneath the right hemidiaphragm .
    OUTPUT:
    
Stable appearance of left pectoral pacemaker and single ventricular lead . No pneumothorax or acute rib fractures .