Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left pleural effusion has increased and is now moderate . The right lung is unremarkable in this patient with an atrioventricular pacemaker and moderate cardiomegaly . There is no pulmonary edema . Right rib fractures are healed and there is calcification of the right coracoclavicular ligament .
    OUTPUT:
    
Moderate left pleural effusion of unknown etiology .