Yes you do indeed have to put down your entire medical history on each application. Your AME then has the information immediately, saving him time and you money! The more cynical amongst us also suspect it catches out those who have selective amnesia as it is hard to repeatedly forget the same thing.... unless you keep a copy of all your old applications
But I have never been asked for repeat documentation - if you have been passed as fit following a medical event that was self limiting that is it. If the event is ongoing (high blood pressure for example) then the AME will reassess it at the examination