Werner Forssmann and catheterization of the heart, 1929.

Invasive study of cardiac anatomy and function traces its origin to the work of a 25-year-old surgical trainee in a provincial German town in the pre-Depression years of 1929 and 1930. Only 1 year out of medical school and undeterred by the medical profession's fear of tampering with the heart, Dr Werner Forssmann explored methods for a more direct access to the cardiac chambers, finding it necessary to make the observations on himself. Later he was able to show that the right-sided cardiac chambers could be visualized radiographically after injection of iodinated contrast materials through a catheter into the right atrium, and again he tried the method on himself.