Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left chest wall pacemaker has two leads terminating in the right atrium and right ventricle in stable position . Median sternotomy wires appear intact . There is a chronic left retrocardiac opacity . The lungs are otherwise clear . Mild to moderate cardiomegaly is unchanged . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
1 . Stable mild to moderate cardiomegaly . 2 . Chronic opacities in the retrocardiac region are of unclear etiology , possibly atelectasis . If patient 's symptoms persist a CT should be considered .