Irregular heart rate

[Den726]

I wanted to upgrade to the charge 5 for the new  heart info but worry about all the problems with it.  I've had the Inspire HR for years and been happy with it.   I was wondering if the new  irregular heart rate notification is just based on your heart rate bouncing around high to low. If so, couldn't you just look at the app graph of your heart rate and if it's bouncing way high to way low, just assume you are having  irregular heart rate.  Would that be what the new function is doing for you?  I could just keep my Inspire and use my graph to determine irregular rate. 

[JohnnyRow]

See How do Fitbit Irregular Rhythm Notifications check for atrial fibrillation (AFib)?  to read about it.  It is much more than that.

Part posted below but recommend read whole article.

That is the passive measurement while asleep or still.  There is a separate on-demand 30 second ECG.

Also  not these features are not available in all countries, not intended for under age 22, not for people with known afib.

[Den726]

Thanks. That explains it better.  Is the premium app required for this irregular notification (not the ecg).

[JohnnyRow]

Can't say for sure but don't think requires premium. One place listing features, with daily readiness score says requires premium, but doesn't say that with ECG or irregular heart rhythm notifications.  Could contact support to verify if still in doubt.

Or maybe someone here can answer that specifically better, though might be tough to tell if it comes with several months of premium anyway and it's not been out that long (or maybe it has).  But could try asking that as a separate specific question for better chance of getting answer.

[charleskn]

So, I love my Charge 5, but with some caveats. 

• Why do the instructions for irregular heart rate notifications preclude people with AFib from using the capability?
• There are two features for heart notifications:
  • Irregular rhythm notifications
  • Notification of High/Low heart rate when at rest
• The ECG/irregular HR determination will be inconclusive if your heart rate is below 50, and above 12.... This is nuts. AFib is often associated with tachycardia, so the algorithm may not work for a large percentage of the population.

[JohnnyRow]

---

@charleskn wrote:

So, I love my Charge 5, but with some caveats. 

• Why do the instructions for irregular heart rate notifications preclude people with AFib from using the capability?
• There are two features for heart notifications:
  • Irregular rhythm notifications
  • Notification of High/Low heart rate when at rest
• The ECG/irregular HR determination will be inconclusive if your heart rate is below 50, and above 12.... This is nuts. AFib is often associated with tachycardia, so the algorithm may not work for a large percentage of the population.

---

@charleskn  I call foul.  You say that for The "ECG/irregular HR determination" but the link you provide refers only to ECG, not to irregular rhythm notifications which are something different.

[charleskn]

@JohnnyRow I would be inclined to disagree. I'd wager that the ECG and irregular rhythm functions are using the same algorithm to collect and analyze the heart rate data. The difference being that the irregular rhythm happens in the background when you're sleeping or at rest, and the ECG is "on demand". I would be VERY surprised to see that they had two different algorithms for these two functions, and different max/min heart rates.

The engineer in me would guess that the maximum heart rate limitation is due the pulse shape and duration from the optical sensor not being responsive enough to discern the differences in the pulse intervals at the higher heart rates.

I am not pooh-poohing the functionality, but it's a real limitation since most arrhythmias are accompanied by either tachycardia or brachycardia.

FTR, here is the manual for the irregular rhythm notifications.

https://help.fitbit.com/manuals/manual_ppg_en_US.pdf

[JohnnyRow]

You may feel free to wager how the internals work, but what you said was that the Help article stated categorically that irregular rhythm detection would be inconclusive with heart rte below 50.  The article you cited does not say that.  The engineer in you may believe that is true, but that article definitely does not say that as you implied.

My point was not to question what is correct (though I do question that), but to question your citing the Help article saying that.

[LZeeW]

@charleskn   My inner engineer tells me that they use two different algorithms.  The ECG and the Irregular Rhythm Notifications are using two different heart rate sources.  The ECG app records a Lead I ECG, so has an algorithm that interprets the electrical activity of the heart.  The Irregular Rhythm Notification uses the optical heart rate monitor.  It uses an algorithm that interprets the beat-to-beat changes in heart rate.  It can't interpret electrical activity, a fundamental part of atrial fibrillation diagnosis.

With respect to users with a diagnosis of Afib, if a user has persistent Afib, then there is no reason to monitor.  There are people who go in an out of Afib.  Fitbit's Help article seems to say that Fitbit doesn't want people to use it as an ongoing monitoring device.