After approval by the Singapore Health Sciences Authority (HSA), users of the Apple Watch Series 4 can now perform an electrocardiogram (ECG) from their wrists, granting unprecedented insight into personal heart health.
This means that users can potentially obtain early alerts for cardiac issues such as arrhythmia and tachycardia – irregular heart rhythms and abnormally high heart rates respectively. It can also potentially identify atrial fibrillation (AFib) by periodically sampling heart rhythms in the background.
Activated with a free update to WatchOS 5.3, ECG functionality is accessible through an app. Heart disease, as one of the largest causes of death in most countries around the world, has been on the rise. Several stories have emerged since the launch of WatchOS and the staggered availability of ECG functionality, of how potentially life-threatening heart conditions have been detected.
The Apple Watch Series 4, released late 2018, sported a revolutionary design with electrodes built into the Digital Crown and body of the watch, enabling a closed circuit across the user’s heart with a finger placed on the crown. This provided sufficient sensor information to create a single-lead ECG recording. Upon completion, rhythms are classified as AFib, Sinus rhythm or inconclusive.
This recording stays private and secure within Apple’s Health app on the iPhone, users having the option to share a PDF of the results with their personal doctors.
Even users of Apple Watches prior to Series 4 can access vital heart information. From Series 1 Apple Watches and after, sporadic read-outs will monitor users’ heart rhythms to scan for AFib or other irregular heart rhythms.
The ECG function on the Apple Watch is built on clinical trials with about 600 participants for AFib and sinus rhythms, and 400,000 for irregular heart rhythm notifications. This means sensitivity of around 98.3% and 99.6% for AFib and sinus rhythm classifications against a top-of-class 12-lead ECG performed by a cardiologist. For irregular heart rhythms, the Apple Watch ECG app detected 80% and 98% for AFib only and AFib and arrhythmias in users that were also tested positive on ECG patches.
Being an intrinsically sensitive issue, users are provided an in-depth on-screen guide that conveys the usefulness and limitations of features, along with instructions for the interpretation of ECG results, along with clear instructions for users with symptoms of conditions.
The WatchOS 5.3 update will be available for users with the iPhone 5s or later on iOS 12.2.
Apple Watch owners can also look forward to an upcoming update that will monitor environmental noise levels to better assist in hearing protection.