Fitbit has finally gone live with irregular heart rate notifications in Europe. The functionality has been available in the United States since March on a select number of devices.

This means that in addition to FDA approval, the company has now secured the CE Mark in Europe. This allows the device on your wrist to be able to passively monitor your heart rhythms for signs of irregularities such as atrial fibrillation (Afib).

The tech works passively while a person is still or sleeping

The regulatory paperwork was actually done by Alphabet Inc, which is the parent company of Google. Fitbit sits under its umbrella ever since the recent acquisition. This filing was submitted in March so the FDA approval for Fitbit’s algorithm came through quite quickly. The CE Mark took a bit longer to secure.

The unique part about this tech is that it analyses wearers’ heart rhythms using the photoplethysmography (PPG) sensors that can be found on most of Fitbit’s wearables. So it is quite different and should not be confused with Fitbit Sense’s (and Charge 5’s) ability to get these types of readings from an ECG sensor. The company already has regulatory approval for that.

The benefit of using PPG sensors is the fact that they work passively in the background by tracking the blood flow in a user’s wrist. The passive monitoring heart feature kicks in when a user is asleep or at rest. It essentially works as a continuous ECG monitor.

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The company’s vehicle to assess how accurately its devices can detect atrial fibrillation (AFib) via a PPG sensor was the Fitbit Heart Study. This has been tested on 450,000 individuals for a while now. To date, the passive monitoring has flagged up more than 5,000 people for a follow up appointment.

Partial results of the study were published last November. They show that Fitbit has an algorithm that is pretty good at spotting undiagnosed signs of Afib. And that such devices could be used for spotting first signs of the condition.

Although there were some false positives, the study demonstrates that Fitbit’s heart rate algorithm, when combined with a wearable ECG monitor patch, delivers a 98% positive predictive value.

Fitbits, therefore, have the potential to be used for massive screening for Afib. Which, in turn, has the potential to reduce medical costs on a wide scale. And save lives. The results were presented at the annual scientific sessions of the American Heart Association.

The feature is rolling out gradually

This Irregular heart rate feature brings the Fitbit on your wrist one step closer to being a must have health and fitness device.

“When your heart beats, tiny blood vessels throughout your body expand and contract based on changes in blood volume”, the company writes.

“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.”

Since the outset, the primary goal of the Heart Study was to secure regulatory approval for Fitbit’s photoplethysmography AFib detection algorithm. Now that it has secured this in a number of countries, the feature is becoming more widely available.

This is the full list of Fitbit devices that are able to access the Irregular Heart Rhythm Notifications. On some of these this is live now, on others it will soon be enabled via a firmware update:

• Sense range
• Versa 2 and above
• Versa Lite
• Inspire 2, 3
• Luxe

You must live in US, Austria, Belgium, Canada, Chile, France, Germany, Hong Kong, Ireland, Italy, Luxembourg, Netherlands, Norway, Poland, Portugal, Romania, Spain, Sweden, Switzerland or the United Kingdom in order to access the functionality. Other countries should follow soon.