There's no device quite as symbolic of the medical profession as the stethoscope. Doctors use it to listen to patients' heart and lung function, and as a way to lay hands on the patient and create a connection. But according to Eko CEO Connor Landgraf, 31, most of the doctors he's talked to don't get much diagnostic value from the instrument: "They didn't feel confident in it.... They were [using it] out of routine and out of habit, and fundamentally did not feel like they could hear the subtle differences necessary to detect heart disease very accurately."

That early market research led Landgraf and his co-founders, Tyler Crouch and Jason Bellet, to launch Oakland, California-based Eko in 2013. The company's digital stethoscopes utilize advances in audio recognition technology to detect heart and lung sounds and pair with an app that uses machine learning to analyze those sounds and flag patterns indicative of heart and lung disease, as well as other defects like heart murmurs. The company has worked through regulatory hurdles and navigated a notoriously slow-moving industry to bring their products to market, raising $125 million to date. Here's how it added its cutting-edge spin to a two-century-old technology. 

Listen to what your audience is telling you 

Eko's first product was a microphone that could be held against a patient's chest, but the early feedback was not encouraging: "We took it to doctors, and they said, 'You know, I wouldn't feel comfortable with this, because the stethoscope has such symbology to it. This needs to look like a stethoscope. I need to understand what it does, and the patient needs to understand what to expect.' "

The feedback led Eko to create an attachment for a regular stethoscope, so that patients wouldn't feel uncomfortable being analyzed by an unfamiliar device. The company now has three products, including a device that looks just like a stethoscope but with a digital microphone built in. Eko also allows its devices to pair with wireless headphones, which was especially useful during the pandemic, when PPE gear and social distancing interfered with doctors' ability to use traditional stethoscopes to monitor heart and lung function. 

Roll up your sleeves 

Eko's devices pair via Bluetooth with a mobile app that analyzes a patient's heart rhythm, checking it against a repository of millions of patient data points from Eko's clinical studies and data collected from the 150,000-plus devices it now has in the field. 

But in the beginning, building that database was a slog, taking the better part of Eko's first four years. Landgraf and his team initially wanted to build algorithms for heart murmur detection, and figured they could collect heart recordings from doctors that had been practicing for years. But they quickly found that much of that data simply didn't exist, and if it did, it was often minimal in scope and stored on antiquated CD-ROMs.

"It became really clear to us that, wow, this is going to be a lot more work," Landgraf says. "We had to build the data set ourselves, which meant that we had to build the hardware, and get the stethoscope out in the market, and get it in clinicians' hands so that we could start to build a data set and make the machine learning algorithms accurate enough."

Getting regulatory clearance was another challenge: The Food and Drug Administration had to understand how Eko's technology worked, and how to categorize it -- which required Eko to submit a good deal of additional documentation. But after about six months of back and forth, the FDA approved Eko's request to operate as a medical device manufacturer.

Be ready to back up your hypothesis

"The health care system is very slow-moving," says Landgraf. "It doesn't adopt new technologies without substantial evidence -- and it shouldn't." He warns other health care entrepreneurs that validation is likely to take a lot longer than you expect. But, he adds, "Medicine is also consensus-driven. And when you demonstrate that the product is better than the alternatives, the standard of care can change quickly." 

To prove that its product worked better than a regular stethoscope, Eko conducted a study comparing its performance with that of expert pediatric cardiologists. "Kids very often have heart murmurs that you can [detect] with a stethoscope, and pediatric cardiologists are some of the best in the business,'' says Landgraf. "We outcompeted four out of the five pediatric cardiologists in terms of total accuracy at detecting heart murmurs that were significant indicators of disease in these patients." Subsequent studies have found that Eko's devices are "comparable" to diagnostic efforts by doctors.

Understand the time scale from the beginning

For Eko, proving its idea took nearly a decade. But the wait was worth it, Landgraf says, because Eko, which has 153 employees, now has hundreds of thousands of health care professionals using its products. He declined to share revenue figures, but Eko's products are priced between $200 and $400, which is standard for most professional stethoscopes.  

"Most things that are worth doing are worth spending a lot of time on and I think in health care you have to think about it in terms of 10 years," says Landgraf. "I think most entrepreneurs should think about it on that time scale...but most people would find that they still make that choice to start a health care company."