- For other persons named Walter Koch see Walter Koch (disambiguation).
Walter Karl Koch (3 May 1880, in Dortmund, Germany – 1962 ) was a German surgeon best known for the discovery of Koch's triangle, a triangular shaped area in the right atrium of the heart, and of Tawara's node, the atrioventricular node which is the beginning of the auricular-ventricular bundle.
Educated in Freiburg im Breisgau and at the Kaiser Wilhelm Academy in Berlin, he obtained his doctorate in 1907 at Freiburg. As a military physician, he served at the Heidelberg pathological institute and the 2nd medical clinic in Berlin. Here he habilitated in general pathology and pathological anatomy in 1921. After being named a professor in 1922, he worked as head of department at Berlin's Westend hospital. Koch became known for his work on the motor centres of the human heart, and coined the term "sinus node".