How Apple Made a Wearable ECG


On Wednesday September 12th 2018, Apple COO
Jeff Williams got on stage at the Steve Jobs theatre and announced that the Apple Watch
Series 4 would come with a built in ECG – or electrocardiogram – giving the user the ability
to see the real time electrical activity happening in their heart. Sort of. It’s technically a rhythm strip, but whatever. This has never been built into directly into
a wearable before and is what scientists would call a big frickin deal. While the accuracy of the reading is for sure
going to be tested in the future, it begs the question: what’s the difference between
this $400 accessory and a full fledged 12 lead ECG? Some quick background: Heart disease is the #1 killer in the western
world, so there’s a need to find arrhythmias, or abnormal heart rhythms. To diagnosis arrhythmias, a doctor will choose
to use a full blown electrocardiogram, usually after a life threatening event or when they
suspect something’s wrong. In the hospital, the medical team will attach adhesive
electrodes in strategic places around your chest and abdomen to get a good recording
of pulses. And different pairings of electrodes produce
what’s called a lead, to make the industry standard 12 lead ECG that looks like this. Great for use in the hospital, but what about
when patients are living their regular lives? Portable ECG units have been available for
a while, but they’d still only be prescribed for a short period of time and only if there’s
a suspicion of finding something. So with any portable unit, you lose the detail
from a full 12 lead. But what you lose in detail you gain in the
continuity. For wearable health tech like the Apple Watch or the FitBit,
the big advantage is the continuous monitoring for people who might not know they have a
heart condition. But while those little green light sensors
on previous Apple watches can pick up the number of beats, they don’t tell you anything
about the electrical activity that caused it. So to get that info without chest electrodes,
developers got the user’s opposite hand involved so they could complete a circuit. The first company to do this successfully
for a consumer product was a brand called AliveCor, which made a watch band for the
Apple Watch that had an electrode built into the band. The user wears the watch on one hand and closes
the circuit with the opposite hand. The Series 4 model does this but with the
digital crown instead of a separate band. But watching the Jeff Williams presentation, and reading
some of the articles that came out afterwards, you notice that the common arrhythmia is Atrial
Fibrillation, or A-fib. That’s because they have the validation of really smart people who have
been testing this in the background for the last few years. A study published in JAMA Cardiology in 2018
took data from almost 10,000 participants with heart rate trackers like the old Apple
Watch – devices only give heart rate and time, which give us graphs that look like this. While these patterns don’t give us a full
ECG waveform, they can still give us hints. Atrial fibrillation looks like this on an
ECG, lots of little waveforms instead of the nice discrete waveforms of normal sinus rhythm. The study used a deep neural network to learn
when it could say “this pattern on the watch data usually goes with A-fib on an ECG”. Then they took that data and applied it to
51 patients undergoing cardioversion, a procedure that helps restore a normal electrical rhythm
to the heart. The study concluded that with this technology,
they could find A-fib with a 97% accuracy. The hope is that the watch will pick up on
something, alert the user to go to the doctor where they get a real deal diagnosis. And with the blessing of the American Food
and Drug Administration, as well as the president of the American Heart Association giving his
personal testimony for the product – there’s a lot of trust behind these results. And Apple is still studying this alongside
Stanford Medicine. That study is set to finish in January 2019. Going forward, it’ll still be a while before
more complex arrhythmias will be detectable, and a $400 watch isn’t gonna touch what
hospital grade equipment can do. But the fact that we now have a tool for screening
one of the most common arrhythmias that people have in a product that people are actually want to buy, is a huge deal. Thanks for watching. This is a bit different than my typical anatomy
and physiology videos, but the new shiny tech was too much to resist. So make sure to check out some of my other
videos and subscribe if you’re interested. Either way, have a great day. Have fun, be good. See you next time.

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13 thoughts on “How Apple Made a Wearable ECG

  1. Great video, clear and informative 😀
    Oh and I bought the series 4 and it's insane compared to the series 0. (I got it for the speed boost and the heart features because I constantly have heart palpitations :P)

  2. As an EMT, this is freaking cool. Instead of having to put a 4-lead or 12-lead with a bunch of stickers on your body and wires everywhere and a big box (with the exception of being able to defibrillate) this is COOL!!!

  3. usually the person does not feel atrial fibrillation. Therefore, continuous monitoring is needed. Here it is impossible, since the measurement occurs only when the finger touches the electrode.

  4. Apparently, Apple Watch has stated that the ECG on the watch will only state if a rhythm is Sinus or AFib. With that being said, do you think a person who knows how to interpret ECGs will be able to identify PVCs, PACs, AV blocks, or AFib-RVR? Lets say someone has one of these rhythms; do you believe the watch will miss interpret the rhythm or will it state something like "inconclusive follow up with provider"? I just hope the ECG is accurate enough for me to interpret just incase I see something other than AFib or NSR on my watch.

  5. Tenho um Apple Watch Series 4 americano e um iPhone X brasileiro e funcionou normal o ECG. Lembrando que tem que atualizar tanto o relógio quanto o celular.

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