Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: In comparison to the chest radiograph obtained approximately 1 week prior , no significant changes are appreciated . Pacemaker leads follow their expected courses through the right atrium , right ventricle , and coronary sinus . Cardiomegaly and cardiomediastinal silhouette are unchanged . Thoracic aorta is tortuous with aortic calcification , unchanged . Lungs are fully expanded and clear without focal consolidation . No pleural effusions or pneumothorax . Degenerative changes of the thoracic spine are unchanged .
    OUTPUT:
    
Pacer leads in expected standard locations .