Apple Watch Able to Detect Abnormal Heart Rhythm With 97% Accuracy
The Apple Watch's built-in heart rate monitor is 97 percent accurate when detecting the most common form of an abnormal heart rhythm when paired with an algorithm to sort through the data, according to a new study conducted by the University of California, San Francisco and the team behind the Cardiogram app (via TechCrunch).
There were 6,158 participants in the study, all of whom used the Cardiogram app on the Apple Watch to monitor their heart rate. Most were known to have normal EKG readings, but 200 suffer from paroxysmal atrial fibrillation (an occasional irregular heartbeat).
Data from these participants, along with data taken from normal Cardiogram users, was used to build a neural network that could recognize the abnormal heart rhythms solely from data collected by the Apple Watch. As of today, Cardiogram says its algorithm can almost always successfully determine when a patient is in atrial fibrillation.
In order to validate the model, we obtained gold-standard labels of atrial fibrillation from cardioversions. In a cardioversion, a patient experiencing atrial fibrillation is converted back to normal sinus rhythm, either chemically or with a shock to the heart. 51 patients at UCSF agreed to wear an Apple Watch during their cardioversion.
We obtained heart rate samples before the procedure, when the patient was in atrial fibrillation, and after, when patient's heart was restored to a normal rhythm. On this validation set, our model performed with an AUC of 0.97, beating existing methods.
Cardiogram is a startup that's aiming to garner more information from the data collected by the Apple Watch. The study, which Cardiogram has raised funding for, started in March of 2016 and will continue as UCSF and Cardiogram work to refine the neural network and detect other conditions beyond atrial fibrillation.
Cardiogram plans to put in additional work before using its algorithm to start notifying Cardiogram users of arrhythmias. The company needs to conduct further testing to make sure the algorithm works in a variety of conditions and it needs to work on scaling it so it can be used continuously by all Cardiogram users.
The Cardiogram app can be downloaded from the App Store for free. [Direct Link]
Popular Stories
Apple is planning to launch at least 15 new products in 2026, according to Bloomberg's Mark Gurman.
Gurman outlined what to expect from Apple in 2026 in the latest edition of his "Power On" newsletter. He said the company is heading "into one of its most pivotal years in recent memory," with the rollout of major new Apple Intelligence features, intense regulatory pressure on the App Store,...
The upcoming iOS 26.1 update includes a small but helpful change for iPhones, and it could prevent you from running late to something important.
Specifically, when an alarm goes off in the Clock app, there is a new "slide to stop" control on the screen for turning off the alarm. On previous iOS 26 versions, there is simply a large "stop" button, which could be accidentally tapped.
The new ...
In his "Power On" newsletter, Bloomberg's Mark Gurman today provided an update on the status of Apple Intelligence and the plans for it in 2026.
Apple is still planning to roll out its revamped version of Siri around March of next year. The release should be accompanied by the release of a new smart home display product with speaker-base and wall-mount options. A new Apple TV and HomePod...
A new Apple TV and HomePod mini could launch as soon as this month, Bloomberg's Mark Gurman today suggested.
In today's "Power On" newsletter, Gurman said that Apple retail stores are planning an overnight refresh on the evening of November 11, where changes will be made after closing, such as refreshing displays and placing new products for the following day.
The timing of the overnight...
Apple is expected to launch a new foldable iPhone next year, based on multiple rumors and credible sources. The long-awaited device has been rumored for years now, but signs increasingly suggest that 2026 could indeed be the year that Apple releases its first foldable device.
Below, we've collated an updated set of key details that have been leaked about Apple's foldable iPhone so far.
Ove...
Apple today released iOS 26.1, the first major update to the iOS 26 operating system that came out in September, iOS 26.1 comes over a month after iOS 26 launched. iOS 26.1 is compatible with the iPhone 11 series and later, as well as the second-generation iPhone SE.
The new software can be downloaded on eligible iPhones over-the-air by going to Settings > General >...
Apple has just given a strong indication that it will not be releasing any additional new Macs for the remainder of the year.
Apple's CFO Kevan Parekh dropped the hint during the company's earnings call on Thursday:On Mac, keep in mind, we expect to face a very difficult compare against the M4 MacBook Pro, Mac mini, and iMac launches in the year-ago quarter.Parekh essentially gave a heads up ...
We're officially in the month of Black Friday, which will take place on Friday, November 28 in 2025. As always, this will be the best time of the year to shop for great deals, including popular Apple products like AirPods, iPad, Apple Watch, and more. In this article, the majority of the discounts will be found on Amazon.
Note: MacRumors is an affiliate partner with some of these vendors. When ...
Apple is about to drop iOS 26.1, the first major point release since iOS 26 was rolled out in September, and there are at least six notable changes and improvements to look forward to. We've rounded them up below.
Apple has already provided developers and public beta testers with the release candidate version of iOS 26.1, which means Apple will likely roll out the update to all compatible...
