New study shows Apple Watch is accurate at detecting irregular heartbeats

A new “study, led by researchers at the University of California, San Francisco, tested the use of the heart-rate sensor and step counter built into Apple Inc.’s Apple Watch, to try to detect atrial fibrillation, a type of irregular heartbeat that can cause blood clots and strokes if left untreated,” Peter Loftus reports for The Wall Street Journal. “Researchers used a mobile application from Cardiogram Inc.— which provided funding for the study — to access the watch data, and a machine-learning network trained to analyze the data.”

“About 2.7 million Americans and 34 million people world-wide are estimated to have atrial fibrillation. Many patients don’t experience symptoms, and it can go undetected until a complication occurs,” Loftus reports. “Researchers say earlier detection could get patients on treatments like blood thinners to reduce risk of complications.”

“Researchers provided Apple Watches to about 50 patients with atrial fibrillation while undergoing procedures at UCSF known as cardioversions to restore normal heart rhythms. Patients were flat on their backs and the watches collected heart-rate data while they were still experiencing irregular heartbeats, and then when normal heart rhythm was restored,” Loftus reports. “The algorithm was able to distinguish between atrial fibrillation and normal heartbeats with about 97% accuracy when compared with gold-standard electrocardiograms, according to results published online Wednesday by JAMA Cardiology.”

Apple Watch Series 3 (GPS + Cellular)
Apple Watch Series 3 (GPS + Cellular)

“But the results were less impressive in a test of the algorithm in about 1,620 people using Apple Watch outside of the hospital in their everyday lives. The watch distinguished between atrial fibrillation and normal heart rhythm with about 72% accuracy, compared with participants’ reports to the researchers of whether they had atrial fibrillation. That means there were a significant number of false positives and false negatives,” Loftus reports. “Researchers said it was more difficult to detect atrial fibrillation in active people because activities can vary heart rates, and the watch measured heart rates less frequently than in the hospital setting.”

Read more in the full article here.

MacDailyNews Take: Obviously, there’s room for the algorithm to improve.

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Apple Heart Study launches to identify irregular heart rhythms – November 30, 2017
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Apple Heart Study could turn Apple Watch into a ‘must have’ for millions of patients – September 12, 2017
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  1. When you look at the progress so far with Watch/Cardio research you can put money on them continually improving their capturing data as well as improving the use of that data.

    Part of this progress is possible because Apple is continually growing the processors and the costs of memory is still falling. We might well see some health app running continually on a low priority core, moving to a primary core when the data moves outside of an expected range.

  2. I was on a flight on Saturday and my Apple Watch S2 told me there was a problem where I was at rest and my heart beat went above 120 about 10 times in 2 hours, I wonder what affect cabin pressure has on the results.

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