Fitbit has made no secret of its plans to get its fitness trackers US Food and Drug Administration (FDA)-cleared for sleep apnea detection; while not there yet, the company has recently made noteworthy progress on related FDA aspirations.

Fitbit just received 510(k) clearance from the FDA (as well as Conformité Européenne or CE marking in the European Union), for its electrocardiogram (ECG) app to assess heart rhythm for atrial fibrillation (AFib). The Fitbit ECG App, unveiled in Fitbit’s recent fall product launch, will be available in October 2020 to users on Fitbit Sense in the United States, United Kingdom, Germany, Austria, Luxembourg, the Netherlands, Sweden, Switzerland, Czech Republic, Poland, Belgium, Portugal, Romania, Ireland, Italy, Spain, France, Hong Kong, and India.

“Helping people understand and manage their heart health has always been a priority for Fitbit, and our new ECG app is designed for those users who want to assess themselves in the moment and review the reading later with their doctor,” says Eric Friedman, Fitbit co-founder and chief technology officer, in a release. “Early detection of AFib is critical, and I’m incredibly excited that we are making these innovations accessible to people around the world to help them improve their heart health, prevent more serious conditions and potentially save lives.”

As part of the submission process to regulatory agencies, Fitbit conducted a multi-site clinical trial in regions across the United States. The study evaluated our algorithm’s ability to accurately detect AFib from normal sinus rhythm and to generate an ECG trace, or recording of a heart’s electrical rhythm, that is qualitatively similar to a Lead I ECG. The study showed that the algorithm exceeded target performance, demonstrating the ability to detect 98.7% of AFib cases (sensitivity) and was 100% accurate in identifying study participants with normal sinus rhythm (specificity).

Fitbit’s new on-device compatible ECG app helps analyze the heart’s rhythm for signs of AFib. ECG is a measurement of the electrical activity of the heart, and the Fitbit ECG App is a way people can take an on-the-spot reading of their heart rhythm at any time, including whenever they notice any unusual cardiac symptoms.

“Physicians are often flying blind as to the day-to-day lives of our patients in between office visits. I’ve long believed in the potential for wearable devices to help us stay better connected, and use real-world, individual data to deliver more informed, personalized care,” says Venkatesh Raman, MD, interventional cardiologist at MedStar Georgetown Hospital and Principal Investigator for the U.S. clinical study on Fitbit’s ECG App, in a release. “Given the toll that AFib continues to take on individuals and families around the world, I’m very enthusiastic about the potential of this tool to help people detect possible AFib, a clinically important rhythm abnormality, even after they leave the physician’s office.”

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Fitbit Sense is the company’s first device compatible with an ECG app that enables users to take a spot check reading of their heart that can be analyzed for the heart rhythm irregularity AFib. Users hold their fingers to the stainless steel ring on the watch while being still for 30 seconds to get a reading that can be downloaded and shared with a doctor.

The new ECG app is part of Fitbit’s broader approach to heart health innovation. Fitbit deployed heart rate tracking on the wrist with its PurePulse technology in 2014, which uses photoplethysmography (or PPG) to monitor the tiny blood volume fluctuations in the wrist as the heart beats.

Both long-term heart rhythm assessment (PPG) and spot check (ECG) technology have important roles to play and Fitbit aims to provide both options to users based on their individual needs. Long-term heart rhythm assessment could give users the ability to identify asymptomatic AFib that could otherwise go undetected, while a spot check approach with new Fitbit ECG App can help those who want to screen themselves for possible AFib and record an ECG trace they can review with their healthcare provider, the company states.

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In May 2020, the Fitbit Heart Study launched to validate the use of Fitbit’s PPG technology to identify episodes of irregular heart rhythm suggestive of AFib. In just over four months, the Fitbit Heart Study has enrolled more than 400,000 participants. Fitbit users in the United States interested in participating can visit the study website or open the Fitbit app to find the Fitbit Heart Study on the Discover tab under Assessments & Reports. The results of the study will be used to support Fitbit’s regulatory submissions globally for its long-term heart rhythm assessment feature.