I'm looking for this batman comic

Hi guys, I'm looking for a comic book issue that I read as a kid back in early-mid 2000's it has an extremely realistic drawing style like Alex Ross's, the most relevant thing I remember is that the whole plot was about batman chasing the joker and Harley Quinn through a hospital or asylum, the joker was wearing a patient coat during this, at the end while facing batman, Harley Quinn shots joker in the stomach and the final panel is batman dragging an injuried and smiling joker.

If anyone could help me finding this issue I will be eternally grateful.