Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy , aortic valve replacement , and left - sided pacemaker device placement with leads terminating in the right atrium and right ventricle . The heart size is normal . The aorta is tortuous and diffusely calcified . The mediastinal and hilar contours are similar . Linear opacities in the lower lobes are compatible with subsegmental atelectasis . No focal consolidation , pleural effusion or pneumothorax is detected . Degenerative changes of the left glenohumeral joint and throughout the thoracic spine are again observed .
    OUTPUT:
    
No acute cardiopulmonary abnormality . Subsegmental atelectasis in the lung bases .