>Werner Theodor Otto Forßmann (Forssmann in English; German pronunciation: [ˈvɛʁnɐ ˈfɔʁsˌman] ; 29 August 1904 – 1 June 1979) was a German researcher and physician from Germany who shared the 1956 Nobel Prize in Medicine (with Andre Frederic Cournand and Dickinson W. Richards) for developing a procedure that allowed cardiac catheterization. In 1929, he put himself under local anesthesia and inserted a catheter into a vein of his arm. Not knowing if the catheter might pierce a vein, he put his life at risk. Forssmann was nevertheless successful; he safely passed the catheter into his heart.
Literally just drugged himself and jammed a tube in his heart at 25 to prove it could be done. And the best part is it turned out to be useful long term and not actually destructive or only temporarily useful.