I have had the original type of Kardia for about five years. I have ‘Advanced Determination’ with mine and I sometimes send results off to be analysed, although not routinely.
About a year ago I started to get a lot of ‘unclassified’ results and I changed the battery in the device and gave the pads a good clean. However, I still got an annoying number of ‘unclassifieds’. Then instead of using the more usual position to get a reading, by fingers on the back of my mobile or on the table in front of it, I decided to use the position described in the original manual, placing one pad of the device just above the left knee, while holding it with the right hand. The correct pad must be placed on the knee.
i stopped getting ‘unclassified’ results.
naturally I wanted to compare the two ways of getting a reading so I experimented quite a lot.
The results made me decide to use the knee, as the results were more definite. I have since had a lot of PVCs and SVEs, but fewer Afib results.
this might just be coincidence of course.
Lately, I have tried alternating using fingers and then knees immediately after each other, and while the results are often the same, using the fingers, I get slightly more Afib results between ectopic results using my knee.
I sent off an Afib result for clinical analysis and it did indeed come back as Afib, but with a yellow score line rather than a red one.
Does anyone know what this means ?
Other than that, other Afib results I have sent for analysis over time have come back - Afib confirmed, NSR, Unrecognised heart rythmn, or Junctional Rythmn.
this being the case, I feel using the knee seems to be slightly more reliable, and my GP said ‘it made sense’, and did explain to me why, but it was a big technical for me !
Only dedicated post-readers will have got this far, so I am hoping there are some opinions out there and perhaps some techy explanations too, as I know some of you are very experienced with Kardia devices.
Thank you in anticipation !
Annie.
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Tellingfibs
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How very interesting ! As a very experienced Kardia user....or so I thought 🤔... and on my second device ( wore out the first one) I didn't know about this knee method. However I've just tried this and it's come back with an AF reading ! Yikes! I shall check throughout the day .....
I'm still intrigued. For past few months I've had alot of SVE readings from my Kardia. Many times when I've looked into these I've noticed what appears to me to be absence of P waves which as you probably know would indicate possible AF.
I've just now felt an episode of ectopics and took a reading on my left knee as you had described and the reading was Atrial Fibrillation .I immediately followed up with fingers only and reading was .SVE. I shall continue taking these sort of readings over the next week or so and see what crops up .
Wow, when I wrote the post I thought I was going to get a lot of replies tactfully suggesting I was mistaken, but with your response I feel I am somewhat vindicated in my suspicions. There might well be a reason that I haven’t thought of, but it is interesting isn’t it. Strange that your Afib seem to be showing up more on the knee and mine with the fingers ! Hopefully we will get to the bottom of it 🧐
"Unclassified" doesn't mean the Kardia contacts aren't working correctly or that the battery is low. It simply means that whatever arrhythmia is being detected, is not programmed into Kardia for detection. One example, of this kind of an "unclassified" reading is atrial flutter.
The "knee" placement on the Mobile is for lead II, as opposed to the usual lead I reading. From the manual "For a Lead II ECG, the left knee should contact the electrode closer to the top of the smartphone or tablet and the right hand should contact the electrode closer to the bottom of the smartphone or tablet."
While one lead can sometimes pick up something another lead cannot, I don't think lead II will be more accurate in picking up afib than lead I and your back to back experiment does not seem to say otherwise. Of course, i'm not an ep, just from my learning.
The other thing is that there are limitations in the automatic readings/determinations of any ekg machine. Be it at your doctors office or with Kardia. That's why it's important to have the actual ekg read by an ep, before making any important decisions.
You probably know that there is now a Kardia 6L, which will use left knee placement to give you six leads, instead of just 1. Since you're getting many "unclassified", it may serve you better. The determinations will still be from lead 1, but the ekg's from the other leads may have important information for your ep.
Good observations. Seems as though the obvious conclusion is that because the 6 lead used on the knee is going to present more information for the algorithm to interpret you will get different results which will distinguish between other arrhythmias?
That's interesting and is similar to my own past experience with my Kardia 6L device. Following a couple of recommendations here, several months ago, I changed from the Kardia to a Wellue device as I found, without the extra monthly payment for "Advanced Determinations", that I was getting too many "Unclassified" results. I think this was likely because I have a timing issue with my heartbeats, i.e. a "wide QRS" thanks to left bundle branch block (LBBB).
I thought I would write because the Wellue works like the Kardia using the fingers, but it also occasionally fails to take a reading on perhaps ten percent or more occasions. In the instructions, however, when this occurs, it advises to use the device with one electrode pressed against either the knee, as you are doing, but, if this fails, to use the left abdomen.
Apparently, the reading using two fingers is much less sensitive than using those other points. If those fail, which has never happened, then the device can also be used with adhesive chest electrodes, which always give a very clear and detailed reading analysed using their free to use and excellent AI, which can be done from 30 seconds up to 5 minutes.
What intrigues me is why anyone would want to use a Kardia on such a regular basis. How do you feel in yourself. Is the AF obvious without the Kardia? I don't see the point of testing yourself every day.
I understand what you are saying, but all this ‘wondering’ has just developed since I was going through a bit of a sticky patch with my Afib, and mostly I found the readings reassuring at that time. However, as the readings became a bit erratic, I found myself wanting an explanation. I am just being a bit pedantic about it, and not wanting to fall into the trap of believing everything the Kardia tells me - especially when I’m feeling vulnerable. The Kardia is probably best when it alerts someone to the possibility they have Afib, when they had no idea about it, then they can get checked by a medic. My brother tried mine ‘for fun’, and so began his Afib journey.
For anyone who only gets lone paroxysmal AF, and has been passed as otherwise fit, then I think you make a very good point. In my case, I can get runs of persistent ectopic beats and mild tachycardia that mimic AF and I find the devices useful and comforting. The AI report from the Wellue has been quite revelatory.
My AF was paroxysmal and frequent for the first 21-22 years and has been permanent though asymptomatic for the last 7-8 years. I went from Paroysmal to Persistent, now agreed Permanent.
You certainly have a good experience of this ailment. My son’s colleague is similar to you but has had five ablations, although now with symptomatic AF and AFl, but is doing okay.
My elderly friend, a quite well 90 year old, also has permanent AF but, apart from some breathlessness, is lucky to have few symptoms and a normal heart rate. He’s also lucky not to suffer anxiety from it - unlike yours truly.
Thomas is my grandson’s name, also, by the way - and I’m secretly hoping he becomes a doubter - or at least a sceptic - in life!
There is an App called Qaly. It is designed to help you interpret Kardia Mobile traces (and other devices).
You send an ECG trace to one of their experienced technicians, and he/she interprets it. I used it because my Kardia sometimes said AF, and the cardiologist looked at the relevant traces from the Kardia, and said all of them were SVEs, not AF.
I also had a 7 day Holter done which found no AF. Lots of SVEs ( a burden of 16% for the week), but no AF.
The cardiologist had another Holter done, and wrote to me saying he could detect no AF.
Qaly's findings agreed with the cardiologist. Lots of SVEs but no AF
Also my Fitbit has never detected AF. Lots of inconclusives which the Qaly tech. interprets as SVEs, or atrial trigeminy.
The only way I can think of to find out for certain if there is any AF is to have an implantable Loop Recorder for a few weeks.
I'm not convinced about the Kardia when AF or no AF is borderline.
As a matter of interest, AF is categorised by the absence of a P wave , along with irregularly irregular QRS complexes. The absence of a P wave is the giveaway
That’s very interesting - thanks for explaining that and for recommending Qaly tech. I think I do need to learn how to interpret the traces for myself, instead of trying on algorithms. Certainly using the knee method I have had more SVE results than Afib, but as I said in a previous post in this thread, I did have an Afib result sent for analysis and it did turn out to be Afib - and that was a ‘finger only’ trace. Immediately before that, the ‘knee’ trace had said SVEs. I do enjoy a good brain teaser ! ☺️
Thanks for replying DiyChas. You are right, it’s easy to become obsessed. As I say though, it’s not so much my Afib I’m obsessing over - rather the inconsistencies that I sometimes find with the Kardia. It’s more of an interesting puzzle for me nowadays. I do have an ecg and echocardiogram every year, which is the most important reassuring thing.
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