Measurement of the QT interval using the Apple Watch

[Carew]

Anyone ever tried these different ways of using the Apple Watch?

Measurement of the QT interval using the Apple Watch

nature.com/articles/s41598-...

[mjames1]

Thanks for posting.

I was notified of a widened QT interval, by my Kardia 6L. Emailed the ekg to my ep and he reduced my Flecainide dose.

I have since recommended not only the Kardia, but also their premium program (may require a monthly fee) that includes the Wide QT determination, especially to anyone on Flecainide or any other drug that has the tendency to widen the QT interval.

Nice to know that the ekg quality of the Apple Watch can also pick up Wide QT although still beyond my pay grade to do that analysis myself

Jim

[KiwiBlake in reply to mjames1]

Hi Jim. Just to clarify, make sure I have this right in my head. I've been on Flecainide for approx 2 years (100mg daily). 3 months ago cardiology put me on a 5 day holter. One of the comments in the report was that I was borderline first degree heart block. My resting HR has dropped in the last 6 months to about 55bpm (previously was about 65). Am I correct in thinking the Flecainide has lengthened my QT interval resulting in a slower resting HR, which is first degree heart block. If that's the case is it reversible once you if I stop the Flec?

Thanks Blake

[mjames1 in reply to KiwiBlake]

Hi Blake, A Prolonged PR Interval and first and second degree heart block are known side effects of Flecainde. If this happens, it's up to your ep whether to continue with the current dose; reduce the dose, or stop the Flecainide completely. This decision will be based on your own individual metrics and medical history.

Because of this, ekg monitoring is suggested "x" days after starting Flecainide an "x" days after any dose increase, or anytime symptons present that warrant investigation.

Beyond my pay grade to speak to the reversibility issue in a global sense, but my ep wasn't overly concerned with my widened interval and block, so based on that, conversations with him and what I've read, I have every reason to believe that in my case it is reversible.

Jim

[KiwiBlake in reply to mjames1]

Thanks Jim for your prompt reply. The senior nurse at our local hospital cardiology didn't seem too concerned. Mine is termed borderline, but I hope it doesn't progress anymore.

[mjames1 in reply to KiwiBlake]

Sounds exactly like the response I got from the ep's PA

[jwsonoma in reply to KiwiBlake]

Hi KiwiBlake,

I'm not a Doc but I think it is actually the other way around. As your HR slows your QT follows but everything slows and stays in sync. They correct QT for HR to accommodate this in the reading.

Flec stabilizes rhythm vs slowing rate. A unwanted side effect is that it can widen the QT interval for all your HRs. The chambers contractions become out of sync as QT gets wider, longer. If QT is too wide, long one chamber has contracted but the other hasn't fully opened in time to receive the blood.

Still I'm not a Doc but that is my understanding. If I'm off maybe some one can straighten it out. My corrected QT has lengthend but it isn't a concern yet. My cardio guy wants me to have an EKG every 6 mos to track it. Good luck.

[Ppiman in reply to mjames1]

Does the Kardia measure and report on QT interval? I was told mine was too wide to use anti-arrhythmic drugs. When I used to pay for the Kardia advanced determinations, I did get advised of “wide QRS”, but not of QT interval.

Steve

[mjames1 in reply to Ppiman]

At least in the US, if you subscribe to "Advanced Determinations", one of those determinations is "Sinus Rhythm with Wide QRS". That's what I got once and emailed the ekg to my ep, who adjusted my Flecainide dose. As to QT interval, above my pay grade to really comment, but they are related. "Measure" and "report" are two different things. Even if the Kardia did not report "wide qrs", a trained ep should be able to see it.

Jim

[Ppiman in reply to mjames1]

Aha - thanks. It’s the same with Kardia here in the UK (except the monthly cost is higher!). I gather both are a result of ventricular conduction abnormalities. A wide QRS is usually the result of a block in one of the bundle branches that innervate it, I was told (which I have).

A wide QT interval is more important to health as if it is too pronounced there’s a chance of life threatening ventricular arrhythmia developing.

Steve

[kitenski in reply to mjames1]

@mjames1 Did the Kardia specifically spot and call out the widened QT intervals? I've just got the 6l as the price dropped on amazon.

[mjames1 in reply to kitenski]

Yes, but you need to subscribe to "Advance Determinations". Depending on what country you're in, it may or may not be available and it may or may not have a monthly fee. Best to check their web site. But even if you don't subscribe, if you send the ekg to an ep, they can see if the QT interval is widened or not.

Jim

[kitenski in reply to mjames1]

Thanks Jim, I just took out their advance determinatons package. Does it call it out in the headline where it reports Afib/ normal etc etc or on one of the other pages?

[mjames1 in reply to kitenski]

Yes, it will say it right in the headline. Also, with that package, at least in the US, you get one free consult with a cardiologist to review an ekg. Plus some other stuff, like inexpensive replacements if lost or damaged and web saving, etc. I'm basically keeping it for the "Wide QRS" determination, because while I can read ekg's pretty well for afib, flutter, PACs, etc, don't feel competent enough yet to discern Wide QRS.

For me, Kardia is one of my lifetimes, so I'm ok paying a little extra. On the other hand, I probably should drop some of the premium streaming channels I hardly ever watch

Jim

[kitenski in reply to mjames1]

yeah thanks you get 4 reviews over here in the Uk. Most annoying is I still get lots of unclassified

[mjames1 in reply to kitenski]

Are you saying you get "unclassified" with the Kardia? Aflutter and some other arrhythmia's are not part of the Advanced Determination list, so they will show up on the Kardia as "unclassified". In that case, simply send the ekg to your ep for analysis. It's all in the ekg.

Jim

[kitenski in reply to mjames1]

yup get many unclassified! One I sent was pacs but they didn’t happen early enough to get picked up

[mjames1 in reply to kitenski]

Yes, "NSR with PVC's" and "NSR with SVE's (usually PACs" are part of Kardia's Advanced Determinations, however if there are too many PACS on the 30 second strip (I think more than 3 or 4) then you will also get unclassified. But again, a good ep will know from the ekg strip and if you take the time you can learn how to read it yourself although not a substitute for an ep reading.

Jim

[kitenski in reply to mjames1]

thanks, this was one earlier, some ectopics but I don’t know enough to say more than that!! Think the big spike was me moving my thumbs. Do you get a clean trace usually? hmm it'd not uploading the screenshot

[mjames1 in reply to kitenski]

I get clean tracings almost all the time with my 6L. The phone should not be plugged into the charger when you take the ekg and sometimes easier to just use the single lead function if you have the 6L. FWIW Kardia only makes its determinations with lead 1 anyway

Jim

[kitenski in reply to mjames1]

managed to post a screenshot below, that is sat in a chair with the kardia on my left knee and my 2 thumbs on the top

[Ppiman in reply to kitenski]

”Unclassified” on Kardia for me was a wide QRS and a rate of over 100bpm. Without paying the tenner a month for “Advanced Determinations”, any wide QRS shows as “Unclassified”, which is mightily annoying.

Since a wide QRS is usually a permanent affair, I’ve given up paying and now use a Wellue AI ECG which gives a whole range of information with no monthly fee.

Steve

[kitenski in reply to Ppiman]

thanks Ppiman , what does the wellue detect? I’m also a bit disappointed that I get so many unclassified after paying extra for Kardia advanced determination.

[Ppiman in reply to kitenski]

Wow. Sorry about those awful typos: a tired day, a phone keyboard, autocorrect and big fingers aren't good.

I still very much like the Kardia, especially for its convenience and handiness but the extra fee is a lot to ask for very little gain, in my view. A couple of people here recommended the Wellue AI ECG a while back and when they offered a good discount I went for it; then they added AI to their smaller and much cheaper handheld device, which I eventually plumped for thinking I'd sell the Kardia (which I'm now doing).

The two give an AI analysis that covers all types of arrhythmia (see image below), but neither, in fact, label "Wide QRS", in fact, or "QT segment" but do give all the timings. The bigger device needs a laptop to get the AI analysis but the smaller one uses a phone app.

I tried to attach images but this website is acting up this evening and won't load them, so I shall give it a go later.

Steve

[Ppiman in reply to kitenski]

See below for my other reply but I found that once you have “Wide QRS” it tends to be permanent and, even with the advanced determinations, a rate of over 100bpm shows as unclassified.

Steve

[KiwiBlake]

Thanks. I'm due for another appointment at Cardiology, so will discuss then.

[kitenski]

working now?

screenshot

[mjames1 in reply to kitenski]

I think "Lead 1" got cropped off. So either send again or just take a single lead ekg, using fingers only.

[kitenski in reply to mjames1]

lead 1 is there the website doesn’t fully load the picture

[mjames1 in reply to kitenski]

Can you just do a single lead ekg and upload that? Otherwise, you might have to reduce the size of your six lead or manually cut off the other leads, print and re-scan. BTW I would be incapable of doing most of what I suggested LOL I think if you're over 30, the internet works you, not the other way around

Jim

[kitenski in reply to mjames1]

I’m quite IT literate, it’s only a small file size wise! Might be an issue with the forum and trying to upload from an iPhone?

Hopefully this link works imgur.com/a/mvz7NZI

[mjames1 in reply to kitenski]

Got it. First of all, you do realize that no one here is an ep or even a doctor, so anything we tell you is just an educated and unprofessional guess that has to be confirmed by your doctor.

That said, the tracing quality looks fine and it appears you have something called bigeminy, which is a fancy way of saying you're in NSR but with a whole lot of organized PACs. "Bigeminy" is not one of Kardia's advanced determinations, so it would show up as just "unclassified".

My suggestion is send this to your ep, or to Kardia's cardiologist for review, if Kardia offers that service where you live.

Alternately, the owner of Kardia, who is also a cardiologist, frequently monitors posts here and posts under "DrDave.." If you open a new thread with the words something like "can anyone help me read my Kardia ekg" there is a likely chance he will show up at some point.

Jim

[kitenski in reply to mjames1]

thanks, I did use one of my reviews from Kardia that was identified as bigeminy and my arrhythmia nurses confirmed.

[mjames1 in reply to kitenski]

You see, I'm not as dumb as I sound (Nice feature calling Kardia, huh, but next time you pay a little )So, as they probably told you, bigeminy is not afib or anything like it. I've had it many times and it usually just went away after a few hours. Again, just a lot of organized PACs. Some people get bigeminy, who never get afib, and stress is sometime the cause, but not always.

Jim

[mjames1 in reply to kitenski]

BTW What does Kardia classify that EKG you posted as?

[kitenski in reply to mjames1]

unclassified

[Ppiman]

The QT segment is said to be hard to measure if there’s also a wide QRS segment on the ECG.

Asking your doctor seems the best route as wide QRS is not the same thing, I gather.

Steve

[Ppiman]

Here is the Wellue list of arrhythmias.

Steve

Wellue AI arrhythmia list.

[kitenski in reply to Ppiman]

Ppiman this one amzn.to/3pnboMe on Amazon says

Note: All of these are shown in APP as 'Irregular heart beat'.

Can you share which model would give more info that just irregular please?

[Ppiman]

And here is the first page of the AI report.

Wellue AI report page 1.

[Carew in reply to Ppiman]

Is that with the Personal ECG monitor (showing at 89.00 USD at the moment)?

I wonder how much more it would tell me, in terms of useful info., over my Apple Watch 8?

Screenshot of Apple Watch 8 ECG earlier this evening.

[Ppiman in reply to Carew]

If all you have is AF, then I think the Apple Watch is excellent and has never got things wrong so far. It shows other arrhythmias but can't label them as Apple don't have FDA or EU approval fr that, I gather.

The Kardia, for £10.00/month, labels a few more, and the Wellue 24-hour device, many more, without an extra monthly fee. The handheld $89 device gives a reduced AI analysis but still lists many arrhythmias. There seems to be an extra 15% at the checkout at present, which is what I received when I bought mine a while back.

Somewhere on the Wellue website, if I recall, it used to say that the handheld device does not offer AI analysis in Europe at present (owing to lack of regulatory approval), but it does give it, despite that. I think that just covers them. The information is not for medical use, only for personal information.

Steve

[Carew in reply to Ppiman]

100% AF, tachycardia a lot of the time, unexplained highly variable heart rate, and I don't know what else!

I felt the Kardia payment system not very appealing. Obviously they have to make money. But the regular payments would severely limit my use of it. I'd always think it was not worth it.

[Ppiman in reply to Carew]

I decided that I couldn’t justify it. The Wellue AI ECG was once only available on Amazon where it is still far pricier than buying direct from the company.

Steve

[Ppiman]

The Wellue gives vastly more information and seems to be very accurate, even though AI. My GP was amazed by it. The small, handheld version will read up to 5 minutes, but the bigger one (using adhesive chest electrodes) can provide a continuous reading of up to 24 hours, which I believe is unique for a relatively inexpensive home device and mightily useful if you have intermittent issues or want to see what's happening while you sleep.

Steve

[Carew]

This is what I assume is meant:

getwellue.com/pages/pulsebi...

[Autumn_Leaves]

Thanks. There’s certainly a lot of potential in these devices.

[frazeej]

I tried this with my trusty Kardia one lead, but I found it physically impossible to place the leads where the article says. (If anyone uses the Kardia, you'll know what I mean).

I routinely, and successfully measure the QT interval on my one lead Kardia printout by just counting the little squares. I can adjust to QTc using one of the familiar formulas for doing so. Comparing my measurement to that of the 12 lead ecg from the cardioguy shows very close agreement (=/- <5%). It's pretty neat!

[Ppiman]

I'm struggling to add a screenshot as this site's web coding is glitchy again! The device from Amazon doesn't seem to include AI analysis, but if you buy direct from Wellue, it does (it's much cheaper that way, too, as there's always a discount). The AI needs to be done on the app on your phone. The device itself only shows "irregular heartbeat" but the app shows much more I'll keep trying to post a screen shot). The 24-hour monitor shows even more detail.

Steve

[Ppiman]

Here's the screen shot.

ECG trace,