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.

Upon graduating from Askanisches Gymnasium [de], he entered the University of Berlin to study medicine, passing the State Examination in 1929.

He ignored his department chief and persuaded the operating-room nurse in charge of the sterile supplies, Gerda Ditzen, to assist him.

However, Forssmann tricked her by restraining her to the operating table and pretending to locally anaesthetise and cut her arm whilst actually doing it on himself.

They walked some distance to the X-ray department on the floor below where under the guidance of a fluoroscope he advanced the catheter the full 60 cm into his right ventricular cavity.

[3] The head clinician at Eberswalde, although initially very annoyed, recognized Werner's discovery when shown the X-rays; he allowed Forssmann to carry out another catheterization on a terminally ill woman whose condition improved after being given drugs in this way.

[3] His surgical skills were noted, however, and he was recommended to another hospital where he worked for a while before leaving in 1933 after marrying Dr. Elsbet Engel, a specialist in urology there.

[1] After winning the Nobel Prize, he was given the position of honorary professor of surgery and urology at the University of Mainz.