FDA clears Fitbit's PPG-based algorithm to detect AFib

The U.S. Food and Drug Administration (FDA) has approved Fitbit's new PPG-based algorithm to detect atrial fibrillation (AFib), a form of irregular heart rhythm that affects nearly 33.5 million people globally, the Google-owned wearable brand said on Monday.

Fitbit's new PPG (photoplethysmography) AFib algorithm allows for long-term heart rhythm assessment that helps identify asymptomatic AFib that could otherwise go undetected. It can passively assess your heart rhythm in the background while you're still or sleeping and you will be notified via the Irregular Heart Rhythm Notifications feature so that you can seek further assessment and help prevent stroke, heart attack or other serious medical events.

Explaining the new PPG AFib detection technology, the Fitbit team stated, "When your heart beats, tiny blood vessels throughout your body expand and contract based on changes in blood volume. Fitbit's PPG optical heart-rate sensor can detect these volume changes right from your wrist. These measurements determine your heart rhythm, which the detection algorithm then analyzes for irregularities and potential signs of atrial fibrillation."

The clinical validation for the new PPG-based algorithm is supported by data from the landmark Fitbit Heart Study, which launched in 2020 and enrolled 455,699 participants over five months. Data presented at the 2021 American Heart Association Scientific Sessions found that the Fitbit PPG detections correctly identified AFib episodes 98% of the time, as confirmed by ECG patch monitors.

The new algorithm will power Fitbit's new Irregular Heart Rhythm Notifications feature, which will soon be available in the U.S. across a range of heart-rate enabled devices.

"We want to make AFib detection as accessible as possible to help reduce the risk of potentially life-threatening events — like stroke — and ultimately improve overall heart health for everyone," the company said.