In 1929, Forssmann was working as a young intern at the Auguste-Victoria Hospital in Eberswalde. The job was hard and often required him to work all day and night without a break. Nevertheless, he was pleased to find a sense of openness among his colleagues and described the situation at the hospital as “precisely the sort of environment in which good ideas could come to fruition.” During his many night shifts, he was preoccupied with the question of how cardiac examinations could be improved. In those days, apart from X-ray images, cardiac diagnostics relied solely on percussing and listening to the heart, as well as on recording its electrical activity by electrocardiography – but these methods were not enough to make a comprehensive diagnosis. Conscious of these shortcomings in cardiology, Forssmann began thinking about how to obtain greater access to the organ.
Forssmann gradually arrived at the idea of using a catheter to examine inside the organ – a procedure that had never been attempted on a living person. He made numerous observations and pored over textbooks and papers on physiology. “After an endless debate about the pros and cons, I eventually decided to act – and that act would become my destiny.” Early that summer, he finally plucked up the courage and took his idea to the hospital’s director, a distinguished physician by the name of Schneider. As was to be expected, the director rejected his proposal: “I’m sorry to say that I cannot provide you with a patient for an experiment of this kind.” Forssmann quickly made up his mind: “Well, then I’ll prove that the procedure is safe by other means – by experimenting on myself.”
From that point onward, everything had to be done in secret. Over the next few weeks, Forssmann planned the experiment down to the very last detail. With a bit of cunning, he obtained some sterile instruments, took advantage of the relative quiet of the lunch hour, and locked himself away in the hospital’s small operating room. In no time at all, he had opened the vein in his left arm in order to introduce a well-oiled ureteral catheter into his body. Once the tube was inserted into his arm, he ran to the X-ray room and used the fluoroscopic screen to check the position of the catheter, pushing it further and further until it reached the right chamber of the heart. “I asked for X-rays to be taken in order to serve as documentary evidence.”
The X-ray images were published, along with a description of his self-experiment, in the journal Klinische Wochenschrift in November 1929. By this time, Forssmann was working at the Charité hospital in Berlin, where he hoped to be able to continue his research into cardiac catheter examinations. The new technique met with little interest in professional circles, however. The famous surgeon Ferdinand Sauerbruch even said: “Capers of this sort are more suited to the circus than to a reputable German clinic.” How wrong Sauerbruch turned out to be.
It wasn’t until the 1950s that cardiac catheterization was put to deliberate use – for example, to study arrhythmia or to take measurements of blood pressure and oxygen saturation in the chambers of the heart. A catheter could also be used to introduce contrast agents directly into the organ in order to visualize the cardiac chambers and coronary vessels more clearly. X-ray monitoring was an essential part of this process. With the Angiograph in 1950, Siemens presented its first specialized system that allowed physicians to observe the catheter on a fluorescent screen as it passed through the blood vessels and into the heart, and to document the flow of contrast agents through the vessels.
Today, cardiac catheterization is a common practice and can be used not only to diagnose a multitude of cardiological diseases but also to treat them directly – and these capabilities are founded upon Werner Forssmann’s daring self-experiment. In 1956, Forssmann received the Nobel Prize in Medicine for the first cardiac catheter examination.