4 ms·

I am working on algorithms related to PVC and AFib detection. I can see why the app might make that mistake. PVCs and AFib are not mutually exclusive, and AFib

I am working on algorithms related to PVC and AFib detection. I can see why the app might make that mistake. PVCs and AFib are not mutually exclusive, and AFib can be "paroxysmal", meaning it doesn't occur all the time. Basically the way AFib "works" is that instead of steady and constant p-waves, where all the cells in the atria contract in one swoop (as they should), the excitation of the cells spreads chaotically without a clear beginning and end. Of course, as a Human watching an ECG you can recognize the PVCs at one glance. AFib can be a lot harder to see, and it can start and stop. Also, AFib seems to be less of a problem than high PVC counts, speaking in general terms. Of course, don't take this as medical advice, I'm just a Veterinarian...

Unklejoe 8y ago
> PVCs and AFib are not mutually exclusive Right. I didn’t mean to imply that they were, just that the watch misinterpreted frequent PVCs as being afib. In my case, it was easy to determine that they were PVCs with a normal underlying rhythm because the underlying rhythm was steady like clockwork, and the PVCs were occurring in a telltale bigeminal pattern for a few seconds at a time. > Also, AFib seems to be less of a problem than high PVC counts I’m no doctor, but this doesn’t align with what I’ve been reading. It seems like they don’t even recommend treatment for PVCs most of the time unless they’re symptomatic. In extreme cases like mine (20,000/day), there’s a chance that it can weaken the heart over time, but I’m not sure how this compares to the risk of stroke for untreated afib sufferers. I’ve heard mentions of PVCs being an indicator for increased sudden cardiac death risk, but I can’t find any reference for this pertaining to people with otherwise normal hearts. I think it may be the case for people who have just had a heart attack or something though. From what I gather, occasional singleton PVCs are generally harmless and occur in almost everyone. Apparently, the issue arises when you start having multiple PVCs in a row without a regular beat in between. After three in a row, it’s considered non-sustained ventricular tachycardia, which is very dangerous, I guess because there’s a chance it might never stop? Once again, not a doctor, so please correct me if I’m wrong. This will probably show up in someone’s Google search one day.
- bayesian_horse 8y ago
  I think PVCs in high counts can accompany more serious problems, like AV Block etc. I had read somewhere that AFib is often not treated. Maybe a statement about what is more serious in general isn't possible because both symptoms can be found in serious conditions.
  - TheOtherHobbes 8y ago
    Afib itself is hard to fix, but persistent Afib causes clotting which can lead to strokes, and sufferers are often put on blood thinners to help minimise their stroke risk.
    - bayesian_horse 8y ago
      There are medications to achieve "cardioversion", meaning transitioning the atria to a coordinated rhythm. Another way is to insert a catheter and use electric shocks to reset the myocardium. But yes, it's not easy.
zelos 8y ago
For AFib, is there likely to be much predictive ability for the watch? Would the watch be able to warn of an onset of AFib before the wearer is aware of it? I was wondering if it was worth buying one for my dad, who has AFib attacks about 3-4 times a year.
- bayesian_horse 8y ago
  The watch is probably not completely reliable, and I don't know how good it is, but from my preliminary experiments in detecting AFib I would guess the detection should be quite useful. Such a watch is probably faster and easier than any other option. Probably not as reliable as 24H ECG for catching transient AFib or a doctor-assessed ECG for manifest AFib, but a lot better than nothing.
sansnomme 8y ago
I like your username
- bayesian_horse 8y ago
  You are probably the first... But thank you ;-)

Unklejoe 8y ago

> PVCs and AFib are not mutually exclusive Right. I didn’t mean to imply that they were, just that the watch misinterpreted frequent PVCs as being afib. In my case, it was easy to determine that they were PVCs with a normal underlying rhythm because the underlying rhythm was steady like clockwork, and the PVCs were occurring in a telltale bigeminal pattern for a few seconds at a time. > Also, AFib seems to be less of a problem than high PVC counts I’m no doctor, but this doesn’t align with what I’ve been reading. It seems like they don’t even recommend treatment for PVCs most of the time unless they’re symptomatic. In extreme cases like mine (20,000/day), there’s a chance that it can weaken the heart over time, but I’m not sure how this compares to the risk of stroke for untreated afib sufferers. I’ve heard mentions of PVCs being an indicator for increased sudden cardiac death risk, but I can’t find any reference for this pertaining to people with otherwise normal hearts. I think it may be the case for people who have just had a heart attack or something though. From what I gather, occasional singleton PVCs are generally harmless and occur in almost everyone. Apparently, the issue arises when you start having multiple PVCs in a row without a regular beat in between. After three in a row, it’s considered non-sustained ventricular tachycardia, which is very dangerous, I guess because there’s a chance it might never stop? Once again, not a doctor, so please correct me if I’m wrong. This will probably show up in someone’s Google search one day.

bayesian_horse 8y ago
I think PVCs in high counts can accompany more serious problems, like AV Block etc. I had read somewhere that AFib is often not treated. Maybe a statement about what is more serious in general isn't possible because both symptoms can be found in serious conditions.
- TheOtherHobbes 8y ago
  Afib itself is hard to fix, but persistent Afib causes clotting which can lead to strokes, and sufferers are often put on blood thinners to help minimise their stroke risk.
  - bayesian_horse 8y ago
    There are medications to achieve "cardioversion", meaning transitioning the atria to a coordinated rhythm. Another way is to insert a catheter and use electric shocks to reset the myocardium. But yes, it's not easy.

zelos 8y ago

For AFib, is there likely to be much predictive ability for the watch? Would the watch be able to warn of an onset of AFib before the wearer is aware of it? I was wondering if it was worth buying one for my dad, who has AFib attacks about 3-4 times a year.

bayesian_horse 8y ago
The watch is probably not completely reliable, and I don't know how good it is, but from my preliminary experiments in detecting AFib I would guess the detection should be quite useful. Such a watch is probably faster and easier than any other option. Probably not as reliable as 24H ECG for catching transient AFib or a doctor-assessed ECG for manifest AFib, but a lot better than nothing.

sansnomme 8y ago

I like your username

bayesian_horse 8y ago
You are probably the first... But thank you ;-)