
The Apple Watch can detect atrial fibrillation: so what now? - vo2maxer
https://www.nature.com/articles/s41569-019-0330-y
======
rtg4869
When you consider this came from research that was funded by Jawbone, Eight
and that the author has equity in InCarda, it makes me question the
authenticity of their claims. Can someone from this field corroborate what is
claimed?

~~~
vo2maxer
The review by Dr. Marcus, a cardiologist [1], refers to a study funded by
Apple and published in The New England Journal of Medicine [2]. His main point
is that “insufficient evidence exists to recommend atrial fibrillation (AF)
screening in asymptomatic adults.” [3] There would be a significant number of
alarmed users with false-positive results who would undergo costly additional
evaluation and treatment where there may be of little benefit. It is
troublesome, in his view, that “private industry has bypassed expert consensus
to initiate screening for AF in the general population.” He adds that “this is
an industry instigated inversion of the relationship between patients and
physicians...” [4] Larry Husten at the Cardiobrief blog gives a good overview
of some of the pitfalls [5].

[1]
[https://profiles.ucsf.edu/gregory.marcus](https://profiles.ucsf.edu/gregory.marcus)

[2]
[https://www.nejm.org/doi/full/10.1056/NEJMoa1901183](https://www.nejm.org/doi/full/10.1056/NEJMoa1901183)

[3]
[https://jamanetwork.com/journals/jama/fullarticle/2695678](https://jamanetwork.com/journals/jama/fullarticle/2695678)

[4]
[https://www.nature.com/articles/s41569-019-0330-y](https://www.nature.com/articles/s41569-019-0330-y)

[5] [http://www.cardiobrief.org/2019/11/13/what-can-we-learn-
from...](http://www.cardiobrief.org/2019/11/13/what-can-we-learn-from-the-
apple-heart-study/)

~~~
tinus_hn
Mr Huston in the last link is complaining that there were too many subjects in
the test and that the test was pretty expensive for Apple. How am I to take
this seriously? It’s just another Apple hater.

~~~
vo2maxer
In regards to your observation, Husten’s review notes that the study [1]
included subjects where the incidence and prevalence of atrial fibrillation
(AF) is low [2], and given the study’s design flaws, its findings turned out
to be largely irrelevant except as a marketing tool with relatively negligible
costs for Apple [3].

I don’t know if Mr. Husten is an Apple hater, but it would be more interesting
if you challenged his actual arguments including those in the study’s
accompanying opinion piece: “The uncomfortable fact is that our personal
health data have considerable financial value to those who want to use them in
the myriad marketplaces connected to our $3.7 trillion health economy.” [4]

[1]
[https://www.nejm.org/doi/full/10.1056/NEJMoa1901183](https://www.nejm.org/doi/full/10.1056/NEJMoa1901183)

[2]
[https://www.ajconline.org/article/S0002-91491301288-5/fullte...](https://www.ajconline.org/article/S0002-91491301288-5/fulltext)

[3] [http://www.cardiobrief.org/2019/11/13/what-can-we-learn-
from...](http://www.cardiobrief.org/2019/11/13/what-can-we-learn-from-the-
apple-heart-study/)

[4]
[https://www.nejm.org/doi/full/10.1056/NEJMe1913980](https://www.nejm.org/doi/full/10.1056/NEJMe1913980)

~~~
tinus_hn
I’m not sure how the fact that data has value is a comment on Apple Health
studies. The health data collected in these studies is not connected on
contact information, so the only thing a user can be profiled as is as a
person who participates in the study. The author is quick to dismiss this data
that first was worth billions as worthless though.

> Now the same sort of breathless optimism about technology is infecting
> medicine and healthcare.

Clearly the author made up his mind before he even started.

> In other words, nearly half a million people were required to identify a few
> hundred people with AF.

Or, the study identified a few hundred people with AF, using nothing but the
watch they were going to wear anyway. Impressive!

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duelingjello
I’m neither partial nor against Apple, but picked up a Series 4 watch recently
with the ECG crown feature. It’s a pain because it only registers when the app
is activated and the opposite arm touches the crown. I’d also consider wearing
a chest strap for constant ECG and sleep apnea monitoring if such a QS device
existed at a reasonable price-point. Lastly, it would be nice if there were a
continuous non invasive blood pressure monitor (CNAP/cNIBP) similar to
CareTaker but more compact and tasteful in appearance that could also gather
data (I have tachycardia and high diastolic BP from unknown causes, in
addition to obstructive sleep apnea because of a Marfan-ish CTD and I’m
overweight).

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copperx
What's not clear is the difference between owning a watch and getting your
annual EKG with your primary doctor? Can the watch detect fibrillation not
detected in your annual? I've never understood that.

~~~
vo2maxer
The Apple Watch used a sensor to intermittently measure changes in blood flow
as long as the user carried the device. The signals then generated pulse
intervals over one minute which ran through an algorithm to infer the presence
of an irregular ventricular rhythm. Further evaluation was conducted for the
group with abnormal results. On the other hand, a 12-lead electrocardiogram
measures electrical activity over a very short period of time. It’s just one
quick snapshot of the heart, therefore, episodic atrial fibrillation can occur
outside that quick peek.

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heinrichf
Alas the article is behind a hard paywall and not available on Sci-Hub...

