I'd like to point you to the wikipedia article of Werner Forssmann, who performed the first cardiac catheterization. Using himself as the test subject. And more

I'd like to point you to the wikipedia article of Werner Forssmann, who performed the first cardiac catheterization. Using himself as the test subject. And more. https://en.wikipedia.org/wiki/Werner_Forssmann https://en.wikipedia.org/wiki/Werner_Forssmann > He ignored his department chief and persuaded the operating-room nurse in charge of the sterile supplies, Gerda Ditzen, to assist him. She agreed, but only on the promise that he would do it on her rather than on himself. 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. He anesthetized his own lower arm in the cubital region and inserted a urinary catheter into his antecubital vein, threading it partly along before releasing Ditzen (who at this point realised the catheter was not in her arm) and telling her to call the X-ray department. 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. This was then recorded on X-Ray film showing the catheter lying in his right atrium.