Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided pacemaker device is noted with single lead terminating in the right ventricle . Heart size is mildly enlarged . Aorta is tortuous . The mediastinal and hilar contours are otherwise unremarkable . The pulmonary vasculature normal . Streaky opacities in the lung bases are compatible with atelectatic changes . No focal consolidation , pleural effusion or pneumothorax is identified . Multilevel degenerative changes are noted in the thoracic spine .
    OUTPUT:
    
Mild bibasilar atelectasis .