Apple’s original Watch shipped with two optical heart rate sensors, mainly for tracking the wearer's heart rate during exercise. Later models added resting heart rate monitoring and alerts, but the device was still basically intended for use with fitness applications. A year ago, the company dipped a wrist into the medical pool, launching a study with Stanford to use the sensors to collect data on irregular heart rhythms and notify users who might be having episodes of atrial fibrillation, suggesting they contact their doctors for follow-up tests—like an electrocardiogram (ECG).
Today, Apple announced that it is building the ability to generate ECGs into its watch. The new Apple Watch Series 4 includes electrodes on the back of the watch (where it touches the wrist) and on the watch stem. To take an ECG, the person wearing the watch launches the app, then touches the watch stem with a finger for 30 seconds. (Putting one of the electrodes on the stem addresses one challenge wearable electrocardiographs have wrestled with—electrodes that are too close together don’t get a good signal.)
The watch then displays its interpretation of the ECG—either a normal rhythm or atrial fibrillation; the full ECG (those tracings we’re familiar with) can be stored as a PDF on the user’s iPhone and sent to a doctor for further interpretation. The device, reported Apple’s Chief Operating Officer Jeff Williams, is certified by the U.S. Food and Drug Administration (FDA); he said that it’s the first certified ECG monitor to be sold over the counter, directly to consumers.
Williams brought American Heart Association president Ivor Benjamin to the stage for an endorsement. Benjamin said, “Capturing heart rate data in real time is changing way we practice medicine. People often report symptoms that are absent during medical visits. The ability to access health data on demand is game changing.”
Apple’s Series 4 Watches with built-in ECG capability will sell from US $399 to $499, depending on other features.
Tekla S. Perry is a senior editor at IEEE Spectrum. Based in Palo Alto, Calif., she's been covering the people, companies, and technology that make Silicon Valley a special place for more than 30 years. An IEEE member, she holds a bachelor's degree in journalism from Michigan State University.