Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left pectoral pacemaker and its leads are in unchanged positions . 3 leads are identified terminating in the right atrium , right ventricle , and coronary sinus . Sternotomy wires are intact . Prosthetic aortic valve is noted . Mild atelectasis is noted in the left lung base . There is no pneumothorax or pleural effusion . Cardiomediastinal silhouette is normal size .
    OUTPUT:
    
Unchanged left pectoral pacemaker and its leads appear in appropriate positions .