Kardia Mobile Mixed Messages

Question for any Kardia Mobile users out there:

Have any of you been given a 'possible a-fib' result and then a minute later a 'normal sinus rhythm.' result? I have persistent A-fib; I don't convert on my own. I have to correct it with cardioversion. However there have been times when my Kardia Mobile resulted in possible a-fib only to give a normal result a minute later after another test. I've asked the question to AliveCor but for some reason they won't touch it with a response other than see my cardiologist,

For the most part I've been comfortable using my Kardi Mobile over the past years but when this happens it's a little upsetting. Was wondering if anyone else has experience this.

Thanks.



Edited 1 time(s). Last edit at 01/19/2024 08:55AM by Myticker.

I don't have your experience, but I'm pretty sure the Kardia uses beat to beat variability to identify afib. Is your rate slow? Perhaps the variability lowers enough to fall within their NSR parameters?

If you want to go to the trouble, you could count small boxes between each beat on an ECG with an afib diagnosis as well as one labeled as NSR. Put the values in a spreadsheet and find the difference between successive box counts. Then look at the differences and see if the afib differences are a lot larger than the NSR ones. There is a conversion factor you could use to convert the box counts to heart rate (BPM), I don't have it off the top of my head, but it is a constant and can be worked out.

You could also plot the differences on the Y axis against cumulative time on the X axis and visually see the differences. It all depends on how much effort you want to put into figuring this out. I've done this manually and automatically before to figure out puzzling rhythms.

Any time I have a question I send a copy of the Kardia rhythm strip to my EP. He usually gets back to me in a day or two with a reading. Is that possible?

It is much quicker to count the interval using the matrix of orange lines typical of an ECG readout. If the Kardia output can be printed, or depicted on a screen as a regular ECG, just count the boxes between R peaks, or from R to T, and so on. Look for interval variability. Not only that, but does a Kardia show P waves? If so, they would be absent in AF. Those two parameters = AF.

Keep in mind that all the automatic algorithms are imperfect and that includes the one on the 16 lead ekg machine at your doctor's office. That is why ep's ignore what they say and simply read the ekg itself.

The ekg strip from the Kardia is perfectly fine for determining most arrythmia's, even more so if you use the Kardia 6L. In most cases, But in some cases -- and it sounds like yours - best to have the Kardia ekg in question read by an ep.

Jim

Well, something is wired!! Today another Possible A-fib from my Kardiacard. This time followed by an "Unclassified" ('Atrial Fib was not detected
and your EKG does not fall within the algorithmic classification of Normal, brady or Tacky). Tried three more times and got two more Unclassified and then Normal. Not very reliable in my opinion. The Unclassified looked normal to me - all peaks were equally spaced. Then I tried again with my 6 Lead Kardia set to single. I got three "interferences" and then finally, Normal.

To verify I was in Normal SR I then took a reading from my Omron blood pressure machine and did not get an arrythmia alert when it completed the test.

This is all very frustrating to me and I'm starting to question the reliabilities of Kardia.Mobile..



Edited 1 time(s). Last edit at 01/19/2024 08:56AM by Myticker.

The Kardia is reliable, but heart rhythms aren't. And I guarantee it's far more reliable than your blood pressure machine. You'll get as much variation from a Kardia as you will from a cardiologist when you're dealing with ectopics and inconsistent rhythms. It sounds to me like you're kind of overusing it and expecting consistent results when your rhythm isn't consistent. Basically, if it doesn't say you're in afib, then put it away because you're not.

Again, the Kardia ekg's are reliable. The automatic analysis is not always. If you can't analyze your own ekg's, then show them to an ep and you will find out exactly what was going on.

Jim

I agree that Kardia is more reliable than BP machines. I’ve been using both for years. But I can definitely say that each time I was in A-fib the BP indicated an abnormal heart beat also. This time it indicated no problem but Kardia gave me three different results - A-fib, Normal, abd unclassified. That to me is inconsistent.
I don’t want to belabor the question to much but why would someone with persistent A-Fib get a positive result one time a negative result 1 minute after? Subsequent tests later during the day all gave normal sinus

Well, here is another possibility. Kardia is subject to interference. Try it in a room with no appliances or electronics running, dampen your fingertips for good contact and watch your posture, not hunching over with your hands way below your chest. These are instructions from Dr. Natale’s nurse navigator when I was getting “Unclassified” readings.

Quote
Myticker
I don’t want to belabor the question to much but why would someone with persistent A-Fib get a positive result one time a negative result 1 minute after? Subsequent tests later during the day all gave normal sinus

That would suggest to me that that person isn't in persistent afib. Persistent afib would give an afib reading every single time.

Remember, an ECG only captures a snapshot a few seconds long. If you're experiencing ectopics and/or afib on and off, one reading might show signs of afib and another one won't; hence, two interpretations. A cardiologist would give the same results if they interpreted each ECG on its own without considering others they've seen from the same patient.

But really, detecting afib is a lot easier than people think. Can you take a pulse? Can you drum a steady beat? If you can do those two things, you can reliably diagnose afib with no devices at all.

And if you have a Kardia or other device and you can count little boxes on a sheet of graph paper, you can also reliably diagnose afib no matter what the machine says. Professional grade 12-lead ECG machines costing $10-15K often spit out interpretations that are utter nonsense too. The first thing you learn in an ECG class is to ignore the machine's interpretation.

Just tried it again and it showed normal. I guess I'll caulk it up to "interference.". It's comforting to know that others may have experience this also. It's just that whenever I see Possible A-fib I have a tendency to freak out and think - here we go again another, cardioversion.

You shouldn't think that until the Kardia has been saying the same thing for hours. There's no reason to rush off to the hospital just because you're having an episode unless your episodes come with more severe symptoms such as fainting, feeling dizzy, chest pain, or shortness of breath. In short, there's no reason to freak out. The anxiety is doing you more harm than the afib is.

You are probable correct. I'm fortunate to be asymptomatic and my episodes happen on average, once a year. My HR may only hit 80 BPM. The downside is I don't know I'm in A-fib so Doc suggested I get Kardia. I also have an iWatch. I'm an avid tennis player and Doc gives me the ok to play as long as I don't have the symptoms you mentioned. I may post a new thread to see if there are any tennis players out there with A-fib.
Thanks for the advice. I will try to take a deep breath with positive results and check again later in the day. It's just that since I have Persistent A-Fib that I didn't expect the result to change. When I ask AliveCor all I get is - speak to your doctor. Thanks again!

I think you're misunderstanding what persistent afib is. Here are the definitions:

Paroxysmal afib = afib that comes and goes (doesn't matter if it stops on its own or by intervention)
Persistent afib = afib that has continued unabated for a week or more
Longstanding persistent afib = afib that has continued unabated for a year or more
Permanent afib = Longstanding persistent afib that you have chosen to just live with and not try to stop

Since you have episodes that come and go, you have paroxysmal afib, not persistent.