Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A dual - chamber pacemaker on the left demonstrates leads in the appropriate position . There is no evidence of a pneumothorax . Mild cardiomegaly is persistent . There is mild bibasilar atelectasis . There is no evidence of a large pleural effusion . The patient is status post aortic valve replacement . There is no evidence of pulmonary edema or focal consolidations concerning for pneumonia . Median sternotomy wires appear to be intact and in appropriate position . The visualized osseous structures are otherwise unremarkable .
    OUTPUT:
    
No evidence of a pneumothorax .