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Fitbit watches will now have a new program that monitors heart rhythms for atrial fibrillation. Sean Gallup/Getty Images
  • Federal regulators have cleared a new algorithm for use in Fitbit watches.
  • Google says the new program checks for symptoms of atrial fibrillation by monitoring heart rhythms.
  • Experts note that the new Fitbit algorithm is part of a growing wave of technology that allows individuals to monitor their health on a daily basis.

The world of wearable devices to help detect a potentially dangerous irregular heartbeat is about to expand.

Google officials have announced that the Food and Drug Administration (FDA) has cleared the company’s use of an algorithm that allows its Fitbit watches to pick up on atrial fibrillation, or AFib, the most common arrhythmia or irregular heartbeat.

People often describe AFib as a rapid “fluttering” of their heart that can leave them feeling weak. Sometimes, however, there are no symptoms.

The Centers for Disease Control and Prevention (CDC) estimates that by 2030, some 12 million people in the United States will have AFib. The danger is that AFib can make your risk of having a stroke five times higher.

In their statement, Google officials say their photoplethysmography or PPG-based algorithm can assess your heart rhythm in the background while you’re sitting still or even asleep. If it detects a rhythm that could be AFib, you’ll get an alert.

That’s when you should let your doctor know so your health team can assess what’s going on.

“I think these devices are a good thing… because they bring more awareness,” said Dr. Randall K. Wolf, an arrhythmia specialist at the DeBakey Heart and Vascular Center at Houston Methodist Hospital at the Texas Medical Center.

“The standard of care has been an EKG (electrocardiogram) in a doctor’s office. But that’s a spot check and not very good at telling us whether someone has an intermittent arrhythmia,” Wolf told Healthline.

“So if we can detect that stroke risk and treat it, we can decrease the stroke rate. That’s a big advantage because strokes are devastating,” he added.

Wolf refers to the technology fueling the devices as part of a burgeoning market.

The Apple Watch also detects arrhythmias and KardiaMobile is a wallet-sized personal EKG device that lets you measure your heart rate and rhythm and capture the data on your smartphone.

Google describes how the new Fitbit feature works this way.

The PPG is an optical sensor that can detect the expansion and contraction of blood vessels and thus your heart rate from your wrist.

The FDA cleared the Fitbit feature. That means the company could demonstrate that its product is equivalent to another device that already has FDA clearance or approval. Lower risk medical devices are usually “cleared” by the FDA.

Fitbit and Massachusetts General Hospital launched a study of the PPG technology in 2020.

Researchers followed more than 450,000 participants over five months during the COVID-19 pandemic. None of the participants had previously been diagnosed with AFib. The study showed that the Fitbit PPG algorithm correctly detected AFib 98 percent of the time.

“There can be a downside. Most of the technology is not perfect. It’s not what we call a 12 lead EKG and there are false positives” said Wolf.

“Something might show up and it’s not important,” he added. “But in medicine there’s a risk-benefit. It may cause a little bit of anxiety to see something on their Fitbit or Apple watch, but the advantage is large. Because they seek medical advice.”

And Wolf says more widespread use of these types of devices may change what we know about arrhythmias.

“We’re finding we don’t know the real incidence of arrhythmias in the U.S. or the world. That’s because we base most of our info on those spot checks in doctors’ offices,” Wolf explained.

“I think we may find the incidence much higher and more common,” he added. “It may be somewhat normal to have a few extra beats here and there when you’re doing something. We don’t know that, but that’s something we’re starting to see.”

Google didn’t say when the new Fitbit feature would be available, but they said it’s coming soon.