A Honeymoon at Siemens

Since 1952, Hertz and the cardiologist Inge Edler had been conducting research into the diagnosis of heart diseases at Lund University in Sweden. At that time, cardiac diagnosis was still in its infancy. Some diagnoses were based on nothing but discussions with the patient and what the physician heard through the stethoscope. If symptoms were more severe, the physician would also use a catheter or X-rays with contrast media to examine the patient. Some diseases were impossible or very difficult to detect with these methods – for instance, heart failure, which is when the heart valves do not close properly and thus allow blood to flow in the wrong direction. One of the tasks that Edler and Hertz set themselves, therefore, was to find a method that could reliably examine heart valve function while being gentle on the patient.

Edler wanted to build medical devices out of old military equipment from the Second World War. Physicist Hertz recognized immediately that old radar units were not suited to their needs – but he suspected that sonar technology had a great deal of potential. If ultrasound waves could locate submarines and steer torpedoes, surely they could also accurately visualize the rapid movements of the kind made by heart valves. In order to test his theory, he visited a shipyard in Malmö, Sweden, which used ultrasound to check welded seams on ships. Hertz held a transducer between his ribs, directing the waves at his heart. When he looked at the screen, he saw the echo of his heartbeat. In May 1953, he borrowed one of the ultrasound materials-testing devices so that he and Edler could experiment with it. Unfortunately, the device was not suitable for advanced examinations. They needed an ultrasound device optimized for medical use – and Hertz’s good contacts at Siemens proved very helpful.

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.

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.