Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is moderately enlarged , and is larger than on the prior study . Prosthetic valves and sternal wires are visualized . There is pulmonary vascular redistribution and increased interstitial markings . There are focal alveolar infiltrates in both lower lungs . While these could be due to pulmonary edema , superimposed infection ca n't be exclude
    OUTPUT:
    
Pulmonary edema . A superimposed infection ca n't be excluded