Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided dual - chamber pacemaker device is noted with leads terminating in the right atrium and right ventricle . Mild enlargement of the cardiac silhouette is unchanged . Atherosclerotic calcifications are noted at the aortic knob . Mediastinal and hilar contours are similar , and pulmonary vasculature is not engorged . Subsegmental atelectasis is seen within the right lower lobe . No focal consolidation , pleural effusion or pneumothorax is demonstrated . There are multilevel mild to moderate degenerative changes within the thoracic spine . Clips are demonstrated in the right upper quadrant compatible prior cholecystectomy .
    OUTPUT:
    
Subsegmental right lower lobe atelectasis . No pneumonia .