Apple Watch versus Kardia ECGs: Both Appear in Your Kardia App But Only Kardia’s Algorithm Identifies Premature Beats

Previously, the skeptical cardiologist described how Alivecor’s recently released Advanced Determinations algorithm identifies both PVCs and premature atrial contractions (PACs.)

I mentioned that Apple Watch ECG did not have this capability:

It should be noted that the Apple Watch ECG algorithm is incapable of identifying PVCs or PACs and Alivecor stands alone as a reliable, FDA-approved resource in this space.

Despite eliminating The Aviation and Peanut M and M’s from my diet, my PVCs persisted and I made some recordings with both my AW and Kardia.

When I looked in my Kardia app I saw both the Apple ECG and the Kardia

Kardia had imported the Apple ECG from the iOS Apple Health app!

The Kardia AI2 algorithm had correctly identified and diagnosed me as having Sinus Rhythm with Premature Ventricular Contractions.

Kardia’s AI2 always correctly identifies my PVCs whether I utilize a single lead or 6 lead mode (both currently utilize only Lead I). Here’s a nice example I recorded this morning after a run on the treadmill of my very premature beat recorded on the 6L.

Apple Watch ECG oscillates between calling my PVCs inconclusive or just normal. Here’s one that Apple called “inconclusive.”

This is a nice feature for those who are utilizing both devices to monitor their heart rhythm (see here for an example of how that works.)

What would really be nice is if the Kardia AI2 algorithm could be used on the AW ECG to let the user know about premature beats, etc. from its Advanced Determinations.

When I asked Alivecor’s Dr. Dave Albert about this he said “We don’t run AI2 on AW recordings as we would need an FDA clearance for that. What you see are the AW interpretations. “

Sometimes beating prematurely,


N.B. My PVCs had abated over the last week coinciding with the elimination of alcohol and peanut M&M’s from my diet however they returned this morning. I did consume an inordinate amount of carbohydrates yesterday culminating in a chocolate chip cookie which could be the culprit.


13 thoughts on “Apple Watch versus Kardia ECGs: Both Appear in Your Kardia App But Only Kardia’s Algorithm Identifies Premature Beats”

  1. Peanut butter cups cause me to have flutters. I can feel it mostly in my lower chest, upper stomach area.. It feels like my heart is going wink wonk on me. At first I thought “no way” so I stopped eating them and my pvc’s lessened by 80%. Possibly the sugar causing them?? Vitamins and food can cause this but my question is can a vitamin or mineral deficiency cause it?

    • If we are talking Reese’s peanut butter cups they do contain chocolate which has caffeine like compounds which can trigger cardiac rhythm abnormalities.
      Dr. P

  2. I experienced irregular heart beats (with occasional “heavy pounding” feeling) at the end of 2011. I went to see a cardiologist. I was instructed to wear a Holter, which confirmed Paroxysmal Atrial Fibrillation PAF. This happened after I took green tea extract for two days (on the recommendation from a friend as a health food). The PAF was most probably triggered by the green tea extract. I was prescribed with Pradaxa, Diltiazem HCL SR and Flecainide Acetate. After two to three weeks, the irregular heart beat stopped. A further Holter test and echocardiogram did not show any AF. I then only drank very very diluted tea occasionally and avoid coffee and alcohol. I am always a non-smoker and only took not more than half pint of bear on rare occasions (about four times a year and totally off since then).

    A year later (2012), took Holter again, no AF detected. In 2015, took an echocardiogram as a follow-up check, things were normal. So it seemed that AF had disappeared or I did not feel it for the long five years after the first PAF diagnosis.

    Then at the end of 2016, I felt irregular heartbeats again. Went to see the cardiologist. Took Holter and echocardiogram again. No AF was detected. The diagnosis this time was Premature Atrial Contractions PAC. The irregular heartbeat happened in the next morning after I dined with a group of friends the night before. After the meal, we stayed and chatted for two to three hours. My friends kept on pouring tea into my cups. I enjoyed very much with the group and kept on drinking without much awareness, badly diverted by the enjoyable chats. My irregular heartbeat came in the next morning. This persisted for about three months and disappeared. Since then I have not touched a drop of tea. I realised that I am too sensitive to tea.

    In 2018, I moved to live with my daughter’s family in another country. Knowing my past health records, my GP sent me to see a cardiologist to see if things were still OK. Took Holter and echocardiogram in April 2018. Results: no AF detected, LV Systolic function remains good with no significant valve disease and mild left atrial dilatation.

    In September the same year (2018), I felt irregular heart beats. Took Holter and echocardiogram again. No AF but PAC was detected. This time, the irregular heart beats appeared two days after taking echinacea pills to fight off a bad cold on the advice from a friend. The irregular heart beats stopped about six months later and have not appeared since then (for two years and nine months now).

    My experience tells me that I am very sensitive to tea (caffeine) and some herds.

    PAF was detected only once ten years ago. Since then I used Kardia to monitor AF regularly until I got the Apple Watch last year. So far, no AF has been detected (multiple Holters and echocardiograms) since the end of 2011. But now I am still on Pradaxa. As what some say: once an AF, always an AF. I guess that the GP and cardiologists do not want to take the risk of taking me off Pradaxa. But I suspect that it may well be an once-off thing triggered by taking green tea extracts. I think that I would be fine if I avoid all caffeine, alcohol and “exotic” herds. In my case, the risk of taking Pradaxa may be higher than experiencing AF again. But who dares to tell me taking off Pradaxa? 🙁

    • Ctaya,
      I work with patients and sometimes we go with a pill in the pocket approach to anticoagulation.
      I’ll be writing about this soon.
      Dr. P

    • I can’t think of any but if you have troublesome PVCs I recommend eliminating all unnecessary vitamins and supplements. Actually, i recommend that to everyone but the only way to know if a vitamin or supplement is creating symptoms is to eliminate them for a couple of weeks

  3. I was diagnosed with pvcs and palpitations. I was told due to my anxiety. I do have severe anxiety. Can anxiety cause pvcs. I can not feel the pvcs and felt fine. I would not have known I was having them if not for my Apple Watch.

    • Did your Apple Watch notify you of the PVCs in some way or are you capable of reading them yourself off the ECG recordings you make?

  4. Dr. Pearson or any reader:

    Are you aware of any consumer device (similar to a Zio Patch or Polar HRM chest strap) that can be worn during exercise (such as running or cycling) and can accurately record and store (on an app or on the device itself) an ECG during the entire (~60min) exercise session? And, also, provide for sending the ECG data from the exercise session to a cardiologist?

    Thank you.

    Paul V.

  5. Thanks always for your informative and often entertaining insights! If food is triggering your PVC’s, you might try the FODMAP diet for a couple of weeks. Designed and now medically credited for IBS, it works by tweaking the Vagus nerve/digestive connection. In my case,
    it almost entirely eliminated my PAC’s. I also noticed that Kardia recently started making calls for ectopics. That said, I’m still a bit skeptical with both Kardia and the Apple Watch in terms of some of their interpretations, and prefer to just look at the tracings which aren’t that hard for a lay person to read at least for basic stuff. I still use Kardia for its clarity and for the six-lead function, but most of the time I use my Apple Watch because of its convenience. Jim


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