The Apple Watch Series 4, and the reality and tremendous value of AFib detection

First things first, I am blown away by the Apple Watch Series 4. As I mentioned in this post:

The leap from Series 3 to Series 4 reminds me of the earlier leaps in iPhone technology. For example, the jump from the iPhone 3GS to the iPhone 4 was like night and day. Though the case looks very similar, the case size (thinner, larger), display, internals, and sensors are a huge leap forward.

One of the big features highlighted in Wednesday’s Apple Event was the addition of AFib detection to Apple Watch. There’s been a lot of discussion on just what the Apple Watch AFib capability really means.

Quartz posted an opinion piece titled, The new heart-monitoring capabilities on the Apple Watch aren’t all that impressive. From the post (via Ben Lovejoy and this 9to5Mac post):

Although the watch can detect changes in the patterns of a person’s heart rate, these changes really only show a user if she has a heart rate that is too fast, too slow, or beating irregularly—signifying AFib. The watch won’t necessarily give the full picture a doctor would need to diagnose a medical issue.


While the watch can legally be marketed to say that it’s able to detect these changes in heart rate and alert the user or her physician—if she so chooses—this doesn’t mean it’ll be nearly as good as an actual medical diagnosis.

While the Quartz piece is certainly correct, the headline is terribly misleading. Many, many lives have been saved by the Apple Watch pointing out a life-threatening condition. Just because the Apple Watch can’t diagnose every such condition, doesn’t mean it doesn’t have tremendous value when it does catch something.

Take a minute to make your way through this detailed Reddit thread posted by an Emergency Physician:

The most comprehensive ECG is known as a 12-lead ECG.

This ECG uses 10 electrodes, 4 on each limb, and 6 in a specific orientation around the heart in order to represent 12 separate vectors across the heart. In some ways you can think about this type of ECG as almost a 3D measurement of electrical activity in the heart.


The Apple Watch ECG is a single lead ECG, measuring Lead I. This is great for measuring the rate and rhythm of the heart which can be very useful for the screening of atrial fibrillation.

There’s a saying about cameras: The best camera is the one you have with you. In the same way, the Apple Watch ECG is the ECG measuring device that you have with you at all times. Though it is no substitute for the 12-lead ECG you’d get at the hospital, it is an amazing screening device that is on your wrist at all times. To use it, you don’t have to make an appointment, take time off from work, and pay a fee for the screening.

Past as prologue, as people start to buy and wear their Apple Watch Series 4, I believe we will start to see a wave of lives saved by this tech. True, the Series 4 ECG is no substitute for a hospital grade 12-lead ECG, but it is the one you have with you.