Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiomediastinal and hilar contours are stable . The right lung is well expanded and clear . There is a moderate - sized left pleural effusion , with atelectasis of the retrocardiac left lung base . Mild pulmonary vascular congestion is seen without overt edema . Multiple sternotomy wires are intact .
    OUTPUT:
    
Moderate - sized left effusion with left basal atelectasis .