Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were provided . Unusual contour of the cardiomediastinal silhouette is compatible with known history of transposition of the great vessels . Dual - lead pacer projects over the right chest wall . Abandoned pacer leads project over the left chest wall and left upper abdomen . The lungs are clear without signs of pneumonia or CHF . No effusion or pneumothorax . Subtle sternal closure device is noted . Bony structures are intact .
    OUTPUT:
    
Abnormal contour of the cardiomediastinal silhouette is secondary to known transposition of the great vessels . No signs of pneumonia or CHF .