Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP portable upright view of the chest . Midline sternotomy wires and prosthetic cardiac valve again noted . The heart is massively enlarged . Bilateral small pleural effusions are noted , slightly increased on the right . There is increased right lower lung opacity which could represent atelectasis versus pneumonia . No overt edema . No pneumothorax . Mediastinal contour is unchanged with atherosclerotic calcifications at the aortic knob . Bony structures are intact .
    OUTPUT:
    
Marked cardiomegaly with small bilateral pleural effusions , slightly increased on the right with minimally increased atelectasis at the right lung base , difficult to exclude a developing pneumonia .