Note: This article was first published on 23 July 2019.
It’s been a long wait but the ECG function will finally be enabled on Series 4 Apple Watches purchased in Singapore via a watchOS and iOS update.
To enable this feature, Apple is required to get approval from regulatory bodies in Singapore such as the HSA (Health Sciences Authority). Who, in turn, have to ensure that the feature works as advertised. All of this takes time.
ECG (or EKG) stands for electrocardiogram. It measures the electrical activity of the heart by plotting a graph of voltage against time. From the graph, doctors can determine if your heart rhythm is normal and also see if there are any irregularities that need further investigation.
You need the latest Apple Watch — the Apple Watch Series 4. If you do, you then need to update watchOS on your Apple Watch and iOS on your iPhone to get the ECG app.
Taking an ECG requires hardware that only the Apple Watch Series 4 has. There are electrodes built into the caseback and Digital Crown that enables the Apple Watch Series 4 to take an ECG. Older Apple Watches don't have these electrodes.
Open the Health app on your phone and you should see a prompt to set up the ECG app. If you get a prompt, you can manually set it up by heading to Health Data > Heart > Electrocardiogram (ECG).
You can start taking your first ECG! Simply go to your watch and launch the ECG app. It's an icon with a heartbeat line.
To start, place a finger using your opposite hand on the Digital Crown. It takes about 30 seconds to get a reading. And as the app says, you should keep your hand still, so I recommend doing this on a desk or any other solid surface. Don't worry, you won't feel a thing during the test. Also, Apple states that the ECG app is not intended for use by people under 22 years of age.
That's because of FDA (U.S. Food and Drug Administration) regulations. Your heart rate and rhythm is partially dependent on your age (toddlers and teens have higher heart rates) and the Apple Watch's ECG function has only been tested to work well for people above 22.
Considering its just a watch, it’s pretty accurate. Clinical studies conducted by Apple found the ECG app to demonstrate 98.3% sensitivity in classifying AFib and 99.6% specificity in classifying sinus rhythm in classifiable recordings. To understand the study in greater detail, you can read the white paper here.
There are four possible results: sinus rhythm, atrial fibrillation, low or high heart rate, and inconclusive. Because I’m no doctor, I’m attaching Apple’s interpretation here:
Unless you are trained to read a graph like the one above, it goes without saying that if you feel that something is wrong or you don’t feel well, you should consult a doctor as soon as you can. You can access all your ECG readings through the Health app and it can even be exported to a PDF for easy sharing with your doctor.
Apple recommends the following:
You can but it is important to stress to them that they should seek help from a doctor if they are feeling unwell. Taking an ECG reading using the Apple Watch is no substitute for a visit to the doctor.
As accurate as the ECG app and the Apple Watch Series 4 may be, I must stress once more that its results are not a definitive verdict on the condition of your heart and that it’s no substitute for a doctor.
It’s also important to note that the ECG app cannot detect the following:
What it can do, however, is provide a doctor and you with additional insights about your health. Long-term insights are invaluable to doctors as symptoms do not always present themselves in the doctor’s office. Furthermore, there have been numerous real-life examples (1, 2, 3) of how the Apple Watch has helped its wearers detect heart conditions that they were not aware of. At the end of the day, if you are feeling unwell, please seek help from a doctor.