Despite initial concerns that it could take years to approve the Watch feature in the UK, support for the serious heart health monitoring feature is now available, having rolled out to US Watch owners at the end of 2018. Apple says the feature is CE marked and cleared in the European Economic Area with clinical trials showing that the ECG app on the Watch delivered an 98.3% sensitivity in classifying atrial fibrillation.
Essential reading: Apple Watch heart rate monitor in-depth guide
Atrial fibrillation, which is also known as arrhythmia,refers to having a quivering or irregular heartbeat. It occurs when erratic or extra electrical signals impact on the heart's natural pacemaker, causing the heart to quiver or beat faster. Having an irregular heartbeat can lead to a stroke or heart failure.
That ECG (electrocardiogram) built into the newest Apple smartwatch uses electrodes to measure the electrical signals that make the heart beat. Those electrodes are built into the Digital Crown and into the back of the Watch. Using the ECG app, which is now available via a free watchOS 5.1.2 update, users can take a 30-second reading by holding their finger to the Digital Crown.
Read this: How to use ECG on the Apple Watch
From that reading, your heart rhythm will then be classified as either AFib, sinus rhythm or inconclusive. Data from those readings will be stored in the Apple Health app on your iOS device and can be saved as PDF files, making it easier to share the information with your doctor or physician.
New heart health features for old Apple Watches
Just as Apple did with the US rollout of its ECG app, it's also bringing the irregular heart rate rhythm notifications for Watch Series 1 or later Apple Watches. Harnessing the optical heart rate sensor, the feature will occasionally check heart rhythms and send a notification if it detects an irregular heart rhythm that would suggest atrial fibrillation.
However, it will only do this if an irregular rhythm is detected on five checks over a minimum of 65 minutes. The feature was part of Apple's recent Heart Study, which included over 400,000 participants to explore whether Apple's tech could be deemed suitable to detect atrial fibrillation.
Along with the UK, both features are also landing in the following countries: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Guam, Hong Kong, Hungary, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Puerto Rico, Romania, Spain, Sweden and Switzerland.
As mentioned you'll need to download the watchOS 5.1.2 update to your Series 4 to unlock the ECG support. The same needs to be done to use the irregular rhythm notification feature if you're rocking an older Apple Watch. You'll also need to make sure your iPhone is running on the iOS version 12.2 to make sure everything is in working order.