Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a single - lead pacemaker device terminating in the right ventricle . The patient is status post coronary artery bypass graft surgery . The heart is mildly enlarged . The mediastinal and hilar contours appear unchanged . The lungs appear clear . There is no definite pleural effusion or pneumothorax , although there is slight thickening of the right minor fissure that may be congestive . Degenerative changes along the thoracic spine are similar .
    OUTPUT:
    
No definite evidence for acute disease .