In 1929, Werner Forssmann inserted a catheter into a vein in his own arm and advanced it into his heart. His risky self-experiment proved that the heart could be reached safely through the blood vessels. Cardiac catheterisation later transformed diagnosis, angiography and interventional cardiology.

Forssmann's performance of the first human cardiac catheterization in 1929 reads like a modern medical parable, exploring themes of courage and the body as a frontier. This event helped to frame the heart as both a lyric symbol and a treatable organ in contemporary poetry.