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 today updated its trade-in values for select iPhone, iPad, Mac, and Apple Watch models. Trade-ins can be completed on Apple's website, or at an Apple Store.
The charts below provide an overview of Apple's current and previous trade-in values in the U.S., according to its website. Maximum values for most devices either decreased or saw no change, but the iPad Air received a slight bump.
...
The smarter, more capable version of Siri that Apple is developing will be powered by Google Gemini, reports Bloomberg. Apple will pay Google approximately $1 billion per year for a 1.2 trillion parameter artificial intelligence model that was developed by Google.
For context, parameters are a measure of how a model understands and responds to queries. More parameters generally means more...
Apple is promoting the new Liquid Glass design in iOS 26, showing off the ways that third-party developers are embracing the aesthetic in their apps. On its developer website, Apple is featuring a visual gallery that demonstrates how "teams of all sizes" are creating Liquid Glass experiences.
The gallery features examples of Liquid Glass in apps for iPhone, iPad, Apple Watch, and Mac. Apple...
Following more than a month of beta testing, Apple released iOS 26.1 on Monday, November 3. The update includes a handful of new features and changes, including the ability to adjust the look of Liquid Glass and more.
Below, we outline iOS 26.1's key new features.
Liquid Glass Toggle
iOS 26.1 lets you choose your preferred look for Liquid Glass.
In the Settings app, under Display...
Apple's online store in the U.S. is suddenly offering a pack of four AirTags for just $29, which is the same price as a single AirTag.
This is likely a pricing error, and it is unclear if orders will be fulfilled. Apple has not discounted the AirTag four-pack in any other countries that we checked.
Delivery estimates are already pushing into late November to early December, suggesting...
Apple in iOS 26.2 will disable automatic Wi-Fi network syncing between iPhone and Apple Watch in the European Union to comply with the bloc's regulations, suggests a new report.
Normally, when an iPhone connects to a new Wi-Fi network, it automatically shares the network credentials with the paired Apple Watch. This allows the watch to connect to the same network independently – for...
IKEA today announced the upcoming launch of 21 new Matter-compatible smart home products that will be able to interface with HomeKit and the Apple Home app. There are sensors, lights, and control options, all of which will be reasonably priced. Some of the products are new, while some are updates to existing lines that IKEA previously offered.
There are a series of new smart bulbs that are...
It's been over a decade since Apple's HomeKit smart home platform launched, and it is overdue for an update. HomeKit and the Home app can no longer keep up with AI-powered solutions from other companies like Google and Amazon, but that's set to change with a smart home revamp that Apple has planned for 2026.
Home Hub
Apple is working on a home hub or "command center" that will serve as a...