Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest are provided . A single - lead pacer is unchanged with lead tip extending to the region of the right ventricle . There is a retrocardiac opacity which likely reflects the enlarged left atrium . There is no evidence of pulmonary edema . No large consolidation , effusion or pneumothorax is seen . The heart remains moderately enlarged . The mediastinal contour is stable . The imaged osseous structures are intact .
    OUTPUT:
    
Moderate cardiomegaly , unchanged with single - lead pacer in place . No pulmonary edema or pneumonia .