# Apple watch ECG function



## Rezillo (28 May 2021)

Having lost a lot of fitness and put on weight in the last two years, I decided to get a cheap watch from Amazon to display my heart rate during any kind of strenuous exercise while I attempted to reverse the passage of time. There was one with thousands of good reviews, so I ordered that. As a watch it was great but the heart rate monitoring was all over the place, displaying a rate when I wasn't even wearing it. That went back.

Mrs R said "What about getting an Apple watch?" so after picking myself up off the floor and with official sanction to spend my life savings, I did. The v6 model, which uses an electrical sensor for heart rate, arrived last week. 

I worked my way through the myriad of functions until I came to the ECG. I ran the 30 second test and at the end there was a chime and a warning displayed that the reading showed signs of atrial fibrillation and that I should contact my doctor. Two repeats, same result.

I googled the watch's ability to confirm AF and although there were reports of false positives for younger people who shouldn't have AF at all, there wasn't much about my age group, which one site said was unlikely to buy one anyway (cheek!). I persuaded Mrs R to try a test, which was completely and repeatably normal, so that at least indicated the watch could work as intended (and good news for Mrs R).

I rang my surgery. 10 minutes later, a doctor rang back wanting to know more. He knew about the watch's ECG function but had yet to come across anyone who had reported issues as a result of using it. We had a discussion about what the watch did and as we talked, I noticed that the watch ECG data appeared on my phone, with an option to create a pdf with graphical output content to send to my GP. He asked me to do this and that he would check it and ring back.

Five minutes later, a very excited GP rang back to say that the output showed classical AF and that I needed to go in to be assessed. What he was excited about was more the watch than my symptoms, as such! He was just very impressed by its output and said that if it verified, it could prove to be the best purchase I've ever made.

An ECG at the surgery earlier this week did indeed confirm AF and I've just had a barrage of tests prior to any anticoagulant use. I would never have known there was anything wrong with me if I hadn't bought the watch - all I knew that I wasn't as fit as I used to be which, given lockdown, wasn't exactly unexpected.

Anyway, very impressed with it all and despite the price, for me, it turned out to be a bargain. Hopefully, the AF has been caught at an early enough stage for treatment before the stroke risk ramps up as I age.


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## fossyant (28 May 2021)

That was some luck, as watches aren't always that accurate, but it's picked up AF then fab.


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## Rezillo (28 May 2021)

fossyant said:


> That was some luck, as watches aren't always that accurate, but it's picked up AF then fab.



Yes, without the watch, by the time I would have realised there was a major problem, it could all have been too late. That was the gist of my conversation with the GP this week.

The electrical heart sensor is what makes the difference to accuracy - the output is in graphical format and looks just like the display screen of ECG gear. Only one sensor, of course, whereas at the surgery, you get plastered with them. The top of the range Fitbit watch has an electrical sensor, I understand, and for Apple, v6 watch and possibly v5

On last week's Have I Got News For You, there was a question involving a scheme to put sensors for similar tests in the handles of supermarket trollies - not sure how serious it was as a proposal, though.

[edit] Found it. https://www.liverpoolecho.co.uk/new...s-trolleys-identifying-shoppers-risk-20615853


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## cwskas (28 May 2021)

Rezillo said:


> An ECG at the surgery earlier this week did indeed confirm AF and I've just had a barrage of tests prior to any anticoagulant use. I would never have known there was anything wrong with me if I hadn't bought the watch - all I knew that I wasn't as fit as I used to be which, given lockdown, wasn't exactly unexpected.
> 
> Anyway, very impressed with it all and despite the price, for me, it turned out to be a bargain. Hopefully, the AF has been caught at an early enough stage for treatment before the stroke risk ramps up as I age.



I'm glad it prompted you to get a follow up on that. Hopefully, it will be no big issue for your future.

A few years back, I was given an older Apple watch by my brother who had bought a new one. I had 5 surgeries in a 15 month period which started with a ruptured colon and ended with me alive but very weak having lost a great deal of weight and spending too much time in a hospital. He wanted me to use it to remind me to be more active during my recovery. The reminders were helpful and I thought the ability to check my pulse was really cool, but didn't really think it was that accurate.

I eventually returned to cycling after a long absence to continue getting healthier. Eventually I bought a newer Apple model with builtin GPS to record my rides. Several months ago, I bought a blue tooth belt to wear when on my trainer and to my surprise it and the watch are almost identical in the statistics they report.

Willie


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## cwskas (28 May 2021)

Rezillo said:


> The top of the range Fitbit watch has an electrical sensor, I understand, and for Apple, v6 watch and possibly v5



I am still using a v4 watch and it also has that capability.

Willie


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## HMS_Dave (29 May 2021)

I have a Casio F21-HR. It's heart rate monitor is fairly accurate to about 10% when i tested it. It gives you a ball park figure. I don't find it all that useful mind, but those with a greater need to monitor their HR would undoubtedly have a more accurate system im sure...


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## Rezillo (29 May 2021)

The Apple pdf contains the complete waveforms overlaid on a graph paper background, so looking here:

https://aclsmedicaltraining.com/rhythm-recognition/

A tested family member's watch result looks exactly like the normal sinus waveform with the peaks either side of the main one and mine looks like the AF one.

[Edit] From the sciencedirect website, here's an image for Apple watches using an optical sensor (top) and electrical sensor (bottom)


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## ColinJ (29 May 2021)

Rezillo said:


> The Apple pdf contains the complete waveforms overlaid on a graph paper background, so looking here:
> 
> https://aclsmedicaltraining.com/rhythm-recognition/
> 
> A tested family member's watch result looks exactly like the normal sinus waveform with the peaks either side of the main one and mine looks like the AF one.


That watch sounds like a _very _good buy for you!

Interesting waveforms in that article. I know that there is something _slightly _odd about my ECG readings because every time I have had one, the paramedics and/or doctors go into a huddle, mutter, and point at the readouts. They then just shrug and ignore it!


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## Captain Sensible (29 May 2021)

After being diagnosed with slight hypertrophic cardiomyopathy a couple of years ago and having just purchased an Apple Watch , my consultant couldn’t praise its ECG function enough. He’d already seen 3 or 4 patients who had self referred themselves to their GP on the basis of the watch’s results and potentially saved themselves a lot of grief later on in their lives.


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