Apple Watch

[Xian1]

Curious to hear from anyone using an Apple Watch ECG app to monitor afib. On mine I can get a reading saying afib and then immediately measure again and get sinus. I recently started taking Dofetilide, so maybe the medication is helping to resolve afib episodes. Any thoughts on how accurate Apple Watch is regarding afib?

[Stentrunner]

I seem to remember a piece of research that indicated that the Apple Watch only picked up about 40% of AF. My own experience is that it’s good at picking it up when the rhythm is very variable, but not when I get runs of AF (with no p-waves) not so markedly out of rhythm. My daughter (A&E consultant) recognises these as AF immediately, but the watch almost never does. I think it works entirely on rhythm and doesn’t monitor for p-waves at all.

[Jackiesmith7777]

Hi

At the moment my husbands Apple Watch series 8 flashes up yellow AF then another time inconclusive we ve never done two in a row straight away but it would probably be inconclusive or AF .

[Decaf_Andy]

I’m a happy user of an Apple Watch to monitor my AF. I mostly know when I go into AF anyway but a test ECG is confirmatory and I can show others (eg wife - a doctor). I have recently started taking bisoprolol/Flecanide and can observe the lower HR and reduced AF load as a result.

However, it strikes me that there are clearly two modes here: an ECG requires finger-crown contact for 30s and so is a two -electrode ECG. Certainly I can see the lack of p-wave when AF diagnosed. The 24 hr monitoring relied upon to give me my % AF load - and, indeed any alarm given to say you’ve gone into AF has no such two-electrode data. I assume that this analysis relies merely on a pulse irregularity test, not a lack-of-p-wave test.

[Peacefulneedshelp in reply to Decaf_Andy]

I use my Apple Watch to monitor my heart rate for exercise. I don't think we want to push our heart rate too high. I like to bike and some of our hills around here can get a little steep and it is nice to be able to set zones for ourselves. As far as AF I use it to confirm the AF as I can feel it way before the watch gives me an alert

[Ppiman]

I think very brief episodes of AF might well be common.

My trusty Apple Watch has proven more accurate than my (otherwise excellent) Kardia, which was fooled by multiple ectopic beats twice (according to my consultant). I note use a Wellue, which with its AI seems marvellously accurate and informative.

What I find with the Watch is that my wrist needs to be quite dry.

Steve

[En85]

Hi, I had afib long standing persistent and all the time (now fixed with recent cardioversion 🤞). Apple watch ECG doesn't pick Afib unless the heart rate is over 120, in my experience. Mine was never picked on ECG but always on the Afib history, showing in my case 100% for over 5 months when I was persistent and now 2% or less. I would allow for 1%-2% error offset, as one week when I was in persistent gave me 99% but I honestly think it was an error or I didn't wear the watch enough.

What I found incredibly helpful is the Heart Rate Variability, before cardioversion mine was between 200 and 100, now it's between 7 and 60-70 (only once I reached 99). The HRV is the standard deviation of the difference between your heart beats picked in small intervals, like 30 seconds or less. I would say that values over 120 HRV are definitely afib, but don't take my words for medical advice, I'm just an engineer 😎

I attach picture for fun, HRV average before cardioversion 150, drop deep down the day of cardioversion and now 28/30 HRV average.

HVR average before cardioversion on 150, after average value is 30

[frazeej in reply to En85]

I've read some conflicting reports on HRV, some saying higher is better (more fit), others saying lower is better, so I don't know what to believe. My Fitbit Sense watch measures "resting heart rate" over a full 24 hour period, in I believe to be 15 minute intervals. I have found that at times when I am inactive-like sleeping- my resting heart rate can jump to 120+bpm for a significant period of time. I take that to me a nocturnal afib episode, as my dreams are NOT that vivid! LOL!

JimF

[Peacefulneedshelp in reply to En85]

I have been trying to understand HRV for some time now, I really don't. I don't know what is an average rate if there is such a thing.

[En85 in reply to Peacefulneedshelp]

It's not an average rate, it's the standard deviation between the differences between the beats. It's not really straightforward, and no one seems to understand the meaning but I personally think that anything over 150 is not right, mine was sometimes over 200. It means the difference between beats is very high, and mine were sometimes jumping from 50 bpm to 100 bmp with me sleeping or just sitting.

[Peacefulneedshelp in reply to En85]

I too have noticed that when mine went high I went into AF. Mine is usually low mine is averaging 21, today. I have read around 50 is optimal, but who knows if that is correct. I also have read that the Apple Watch calculates differently than other devises, (of course it does) What throughs me is the term standard deviation, in my mind if there is a deviation in the standard, shouldn't there be a standard? In trading, there also is a standard deviation, I tend to think it is same for our heart beat. It is different for each of us. So what our norm is, is then calculated by the deviation in the beat. the higher the number it is more erratic beat, the lower the number is more even beat according to our heart standard heart beat. Now that I have written that out it makes sense.

If that is wrong please feel free to correct me.

Peace,

[Buzby62 in reply to Peacefulneedshelp]

HRV is always high when you are in AF, it’s not the cause of your AF episode. I used my AppleWatch for a few months before it alerted me to an AF episode, it will only alert you after several background checks over several hours indicate your beat to beat measurements are varying from one beat to the next over several checks, hence the message that it shows signs of AF which you can confirm with an ECG measurement. I can look at my HRV history in those few months when I was blissfully unaware of my AF and am pretty certain I had episodes on days when my HRV spiked.

I would advise that you should ignore HRV when in AF as it has no significance and will be high because of the AF.

[Peacefulneedshelp in reply to Buzby62]

I Know what you are saying. But we are missing each others point so I will leave it at that.

[En85 in reply to Peacefulneedshelp]

Yes, we were talking about the interpretation of the data I think you summarised it well, I'm a data engineer and worked with standard deviation but I find it hard to explain lol I find Wikipedia a good reference en.m.wikipedia.org/wiki/Sta...

As you said when the beats are close to each other in value, the HRV is low, when the heart is jumping randomly (this was my case) the HRV is very high. When I look at the beats to beats measurements, the maximum jump I get, now occasionally if I'm suddenly walking fast or stand up quickly, it's 10. Before cardioversion, when I was in constant AF jumps were all sorts (never two consecutive beats the same) and often 20 or more, sometimes as I said 50 between a beat and the next, even if I was sleeping, and that produced HVR of over 200 which I'm assuming, it's really not normal. The few studies I found about HVR states different ranges for healthy heart but no one is even considering values over 105 ms. The maximum I had after cardioversion was 99 ms, and this is in the ranges considered usual, normally is around 30 ms, when I sleep around 15 ms unless I slightly wake up.

I hope it helps 🤗

[Rick-Will]

I have PAF and my Apple Watch is series 6

I wear on my left wrist tells me I’m in AF but sometimes I change it to the right wrist and do a second reading it tells me I am in sinus rhythm, I know I’m in AF so take no notice of it , but I keep the recordings to show cardiologist.

[Hallju]

My EP compares my watch data to my pacemaker reading and usually resets the pacer to make sure it is catching the aFib accurately. However, I confirm my watch data with what I actually feel. I have my watch set to only give readings when I manually check it. And, yes, there are times that I know I’m in AFib but then it goes away quickly, which is confirmed by the Apple Watch as back up data. And, as attached, mine records even way below the 120 as mentioned by En85 . I’m not sure if there is a setting that changes that or not.

Afib

[En85 in reply to Hallju]

I checked again and I saw that the watch picked AF in 11 occasions but I can't really trust it in my case because when I was in persistent most of the times would flag "inconclusive" or "sinus". I found the AF History much more reliable. There must be something the software looks at to identify AF on the ECG, I wonder what 🤷🏻‍♀️

Most of ECGs were taken while in persistent AF, but only 11 have been identified as AF.

[Popular9]

I am using an Apple series Ultra. It is extremely accurate. The watch has recorded 122 times I was in Afib during the last year. I had been asking my now ex-regular physician for a referral to a cardiologist for over a year and his advise was just go to the hospital if I thought I was in Afib and that the watch was a toy. Four days after my last visit to him I had a stroke. I passed out and when coming to I realized I was in trouble with body numbness and loss of speech. I ended up being in Afib for 15 hours with a HR of 207+ as the excitement continued in the hospital. I was lucky with no permanent stroke damage. My new cardiologist swears by the watch as he was one of the many physicians that was invited by Apple to review the capabilities of the heart features on the watch. In looking at some of the posts here there are some things I have learned about tracking with the watch. Most of my episodes were in the middle of the night - many times the heart beat did not exceed 110. You must go through all the settings on the watch to fit your lifestyle. Set maximum and minimum heart beat notifications. How your watch is set in focus and sleep settings will control when you receive notifications. Always check the time stamps. The watch will check daily at random times but once in Afib it will check every 2 hours. Look at your corresponding heart beat during those times. When returning to sinus rhythm after the last Afib notice you can determine how long your have been in Afib by the notices. If you are just feeling weird and not sure about what your heart is doing use the stem to take an EKG. I am currently on a very low dose of Sotalol (40/40) and Eloquis (5/5). I am staying out of Afib by addressing every possible trigger point. No caffeine, no alcohol, almost no artificial sweeteners particularly Aspertame, low fat, minimal added sugars, low salt and a more plant based diet. I clock my sleep habits, walking and swimming daily. I’m at a good weight now and clock all food I consume in MyFitnessPal. It is a new lifestyle but I have no complaints on my quality of life and how I feel.

[Peacefulneedshelp in reply to Popular9]

I am glad he is your ex doctor. Why don't doctors listen? that is the million $ question. Ego I guess.