A rubber tube to the heart

The origins of cardiac catheterization

While slipping quietly through the rooms of the Auguste-Victoria Hospital in the German town of Eberswalde in Brandenburg, the young assistant physician Werner Forssmann (1904-1979) devised a highly unusual experiment – with himself as the subject.

His plan: to thread an oiled rubber urinary catheter through his veins all the way to his heart, so that he could examine it via X-ray. Although it has since become an indispensable and commonplace procedure in cardiology, in 1929 the very idea of cardiac catheterization seemed insane. Nevertheless, Werner Forssmann dared to attempt it. While a small number of doctors had previously experimented with vessel catheters on cadavers and animals, the procedure had never been tried on a living human. Before Forssmann put his ideas into practice, cardiac examinations had been performed mainly by using X-ray images or electrocardiograms.

A clandestine experiment in the lunch hour

Forssmann planned his first self-experiment in great detail, demonstrating both courage and ingenuity. He made use of the hospital’s relatively quiet lunch hour to keep his plans secret. His experiment was not supported by
colleagues or the head physician at the time. Nonetheless, he succeeded: With the catheter already in his body, he ran to the X-ray room, where he completed the procedure and documented it in the form of an X-ray image. In his memoirs, Forssmann later wrote that “introducing the catheter to a distance of 35 cm was child’s play.” In a second attempt, he reached the right atrium after 65 cm. The image of Forssmann’s heart with the tube inside is among the exhibits on display at the Siemens Healthineers MedMuseum in Erlangen.

Medic or madcap?

In November 1929, the journal Klinische Wochenschrift published an account of Forssmann’s experiment. However, his unconventional methods were initially met with little interest from his peers. By this time, Forssmann was working at the renowned Charité hospital in Berlin, where he hoped to gain the support of surgeon Ernst Ferdinand Sauerbruch. However, Sauerbruch was so angered by Forssmann’s self-experiment and publication that he fired him instead, remarking that “capers of this sort are more suited to the circus than to a reputable German clinic.” Of course, he could not have been further from the mark – to this day, cardiac catheterization remains the gold standard for diagnosis and treatment of coronary heart disease. In this procedure, X-ray monitoring is crucial to imaging of the catheter and blood vessels.

Crucial X-ray monitoring

In 1950, Siemens unveiled the first dedicated angiography system, the Angiograph, at the International Congress of Radiology in London. A special mechanism enabled a series of heart images to be recorded. The device was also used for monitoring purposes during cardiac catheter examinations. In 1972, Siemens presented its first special workstation for the cardiac catheterization lab: the Cardoskop U. This entirely innovative system greatly simplified procedures by rotating around the patient.

Re-opening blocked arteries with balloons

Another milestone in the history of cardiology is the method developed by physician Andreas Grüntzig (1939-1985) to re-open blocked arteries without surgery. Grüntzig pioneered the technique of placing a balloon on the tip of a catheter, guiding it to the blockage, and dilating the vessel from the inside. He first used the method in February 1974 on a patient with a blocked leg artery at Zurich University Hospital. Three years later, on September 16, 1977, he succeeded in unblocking a narrowed coronary artery in a world first. The procedure, which represented a major breakthrough in interventional cardiology, became known as percutaneaous transluminal coronary angioplasty (PTCA), or simply the “Grüntzig Method”1, and brought him world fame. Initially, Grüntzig also had to overcome resistance in the medical community, but his passion and natural curiosity ultimately enabled him to succeed like Werner Forssmann2 before him.

Werner Forssmann was eventually rewarded for his bold self-experimentation: In 1956, along with André Cournand and Dickinson Richards, he was awarded the Nobel prize for medicine in recognition of his groundbreaking work on cardiac catheterization.

Cardiac catheter examinations

Cardiac catheter examinations are minimally invasive interventions. They provide an important way to diagnose and treat a wide range of heart diseases. One example is assessing coronary vessels by means of coronary angiography, in which contrast medium is injected into the vessels. If the examination reveals narrowing or blockage, the affected vessels can be dilated using a special balloon and treated by inserting a mesh tube known as a stent. Around 1.1 million3 cardiac catheter examinations are currently performed each year in Germany alone. In around a third of these, the coronary vessels are treated in the course of the intervention itself.

1Beck, Andreas Andreas Grüntzig. Eine Idee verändert die Medizin. Clio-Verlag Konstanz, 1995, p. 97


3Figures for 2017: examinations in Germany: ~ 1,156,650, with treatment (PCI): 408,010 Source: Decision Research Group Data, Welt ~