Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well expanded . A retrocardiac opacity obscures the left hemidiaphragm . There may be bilateral small pleural effusions . No pneumothorax is visualized . Cardiomegaly is moderate - to - severe . Dual - chamber pacing leads project over the expected positions of the right atrium and right ventricle .
    OUTPUT:
    
1 . Moderate - to - severe cardiomegaly . Retrocardiac opacity may represent infection or volume loss . 2 . Small bilateral pleural effusions are difficult to exclude .