They caught the erratic heartbeats in 92.9 percent of patients who had it, and correctly identified 97.7 percent of patients who didn't.

In a study published in July in the Journal of the American Heart Association, researchers used the app to screen a little over 1,000 patients for atrial fibrillation. Researchers used this phone-based device to detect atrial fibrillation. The concept is similar to a pulse oximeter or wrist wearable.

One iPhone app, called Cardiio Rhythm, monitors the heart using a phone's camera. Right now, the only way to detect it is with an electrocardiogram, or EKG, which involves visiting a medical professional and using a machine to monitor the heart's electric signals. Since this condition can come and go, there's no guarantee that doctors will catch the errant heartbeats. It's possible to be experiencing atrial fibrillation and not know it. Patients with atrial fibrillation are five times more likely to have strokes, and it affects 9 percent of people over 65. Screening for atrial fibrillation has gotten a lot of attention, because this irregular heartbeat can cause blood clots, parts of which can break off and move to the brain, causing stroke. Some are designed for home use, while others are for health care providers. In a statement provided to NPR, Fitbit says that 'Fitbit trackers are not intended to be medical devices' and that internal research shows that their trackers meet 'industry standard expectations for optical heart rate on the wrist.'īut there are growing numbers of heart-monitoring apps that are intended to be used as medical devices, which unlike fitness trackers have to be approved by the FDA. A class-action lawsuit filed against Fitbit in early 2016 claimed just that. This isn't the first time wrist-born heart rate monitors have been called inaccurate. If you have dark skin, a tattoo or a birthmark where the monitor sits, Gillinov says that can confuse the monitor. The heart rate monitors in Fitbits and Apple Watches work the same way, except they shine the light through your wrist. 'We often have to move the monitors around because we lose the signal,' says Gillinov. Hospital pulse oximeters are wrong all the time. By measuring changes in reflected light, pulse oximeters can track how fast your heart is beating. Different amounts of light bounce back depending on how much blood is flowing. Those are pulse oximeters - they measure heart rate and oxygen content by shining a light through your skin. If you've ever been in a hospital, you might have had a little plastic clip attached to your big toe (or your ear, or your finger). Part of the problem is how they work, he explained. 'For those groups, I'd recommend medical-quality chest-strap monitors,' says Gillinov, adding that he doesn't think that inaccurate heart rate monitors are dangerous, just that they might not be useful. But for elite athletes and cardiac patients who try to keep their heart rates in certain ranges, these devices might not be the best choice. The others fell in the 80 percent accuracy range, both overestimating and underestimating wearers' heart rates.įor most people, errors like these aren't a big deal, says Gillinov. Overall, the Apple Watch and Mio Fuse did best, with about 91 percent accuracy. The study was designed to find out whether those readings are accurate. Marc Gillinov, a cardiac surgeon at the Cleveland Clinic and an author on the study. Many of them are very concerned because they've recorded values that seem way outside of the normal range,' says Dr. 'We have patients come in who have different kinds of monitors like these.

Heart rhythm tattoo