Increased opacity in the left mid and lower lung zones with a likely increasing small left pleural effusion, which could represent atelectasis as evidenced by the elevated left hemidiaphragm. Differential considerations include developing infection or sequelae of aspiration, although assessment is limited due to overlying pacemaker generator.
Atelectasis (Uncertain) Pneumonia (Uncertain) Simple pleural effusion (Present) Aspiration (Uncertain)