From 1935 to 1945, Hertz’s father, Nobel laureate Gustav Hertz, had been head of a Siemens research laboratory founded especially for him. (Gustav’s uncle Heinrich Hertz is equally renowned – the physical unit of frequency is named after him.) Hertz contacted Siemens and combined a visit to the medical technology division with a private occasion: A few weeks after he had watched his own heartbeat at the shipyard, he married. On their honeymoon in Germany, he left his wife alone for a few hours while he went to meet Siemens director Wolf Gellinek at the company’s medical technology headquarters in Erlangen. Hertz borrowed a device that was equipped with a special camera that allowed the examination results to be stored and compared. Back in Sweden, he and Edler got to work at the university with a number of younger researchers. On October 29, 1953, they scanned echoes from the heart, first as A-mode signals. The camera then visualized the heart function as a curve – which was the invention of the M-mode and the first non-invasive representation of heart function in medical history.
In December, Edler and Hertz traveled to Erlangen together to work with Siemens engineers on further improvements. Among other things, they optimized the device with “a field of view that only displays the medically interesting pulses,” and with aids that helped physicians guide the transducer correctly. Edler and Hertz also received a specially designed transducer that could be inserted into the esophagus and thus enable even more accurate examinations. From then on, Edler became almost inseparable from the ultrasound device. He took it home with him on many weekends and on vacation to his summer house – he was even seen with it on Christmas Eve. His wife and four children supported him, sometimes serving as test subjects. His son Anders, for instance, allowed Edler to examine him at home with the esophagus transducer.
After two years of research, the results were substantiated to the point that Edler could rely on ultrasound diagnostics for various heart examinations. By 1956, the process was already so accurate that it detected a tumor in the left atrium of the heart. In 1958, a newly developed Siemens transducer made it possible to examine the structures of the heart. However, it was a few years before the process became established worldwide and took the name we know it by today: echocardiography. In recognition of their breakthrough, the two pioneers received numerous awards – for instance, Edler was voted Sweden’s cardiologist of the 20th century, and he and Hertz both received the Lasker Award, which recognizes measures and programs that aim to improve human health and extend human life.