The AliveCor Kardia Mobile ECG is an amazing bit of kit, both for medics, but also patients. A smaller than a credit card, and able to provide an accurate ECG trace of your heart in 30sec! But is this something which is useful to Joe Bloggs? What about Joe Athlete?
AliveCor Kardia Mobile ECG Review
There are lots of bits of kit used in the doctor’s surgery, and some of it, such as a stethoscope, or a blood pressure machine can be easily purchased without having to go through medical school. But most people don’t buy stethoscopes, for example, as they don’t have a use for them – fancy dress parties excluded! Conversely many people do buy a blood pressure machine in the high-street, such as the Withings offerings, as people like to monitor their blood pressure at home. So why might the AliveCord Kardia Mobile, given it’s focus is significantly more complicated than a simple blood pressure reading, be marketed in such as way as to suggest it deserves a place in patients homes?
Part of the reason for the Kardia Mobile to be available to the public is the increased level of biometric monitoring which is now considered normal – how many people walk around with a smart watch or activity tracker with 24/7 heart rate monitoring? Now broadly I don’t think that 24/7 HRM is that useful to Mr Smith in the street. Well certainly not the raw, unprocessed data, however an analysis of the data can be very beneficial.
There have been plenty of newspapers reports where an Apple Watch has alerted at patient to an abnormal heartbeat and has potentially saved their lives, resulting in the cultural zeitgeist being that this level of connectivity with our technology is now normal. These very positive Apple Watch stories do underline my previous point, that the winning factor here is not the 24/7 monitoring, but that the Apple Watch was able to analyse the data it was receiving, and provide the owner with a useful interpretation of that data.
The Alivecor Kardia allows for a more specific variation of that, in it allows a patient at home to monitor their cardiac rhythm, ie how the heart is beating, rather than the rate or speed. This data can then be analyzed by the companies Kardia app, to give a NICE (UK) and FDA (USA) approved comment of; Normal, Possible Atrial Fibrillation, or Unclassified in terms of heartbeat patterns
– note that the app is NOT going to diagnose you have a problem, merely strongly suggest you speak to a medical professional. So never the less, the app, and the analysis is where the real strength of the product lies, but this is further enhanced by the ability to forward the recorded ECG to a Kardia doctor to formally analyze.
This is properly cutting edge personal health. A patient feels that they have an irregular heartbeat at times, pops to the doctor who finds things are normal. The analogy here being that if you tell someone it has been sunny today, they look out of the window and it is raining, it doesn’t mean it hasn’t been sunny, just there is no evidence currently. This happens a LOT when dealing with intermittent cardiac arrhythmias – normally we request an outpatient cardiology appointment for the patient to wear a 24hr monitor – but these are EXPENSIVE. With the idea of personalized medicine, a patient is able to purchase a Kardia, and take an ECG recording when they are getting the sensations and hopefully capture the abnormal rhythm. They can then provide a copy to their doctor who can incorporate that into the ongoing investigations as to what it going on hopefully allowing the patient to improve their own health care – very 21st Century!!
NOTE I AM NOT SAYING REPLACE A DOCTOR HERE – I’D REFER YOU BACK TO MY PREVIOUS COMMENT THAT IT IS NOT THE DATA ALONE WHICH HAS THE POWER, BUT THE TRAINED ANALYSIS
So at this point it should be clear that this is not a product for everyone. In which case who should be reading the back of the box saying, “Yup I’m worried about atrial fibrillation, and some of that peace of mind? Sure I’ll take a serving of that as well thankyou!
Perhaps we need to have a little look at what atrial fibrillation is:
Atrial Fibrillation (AF)
Interestingly enough the AliveCor site doesn’t go into any particular detail as to what actually is.
OK so here comes the science. If feel your pulse at the wrist, you’ll (hopefully) get a regular pulse 1…1…1…1…1, ie. the pulses coming after each other at the same intervals, you’ll also be able to time the rate, ie. how many beats per minute – hopefully, less than 100 BPM. As a shorthand you can count the pulses over 6 seconds and then multiply by 10 to give an approximation of your BPM.
Now if you LISTEN to your heart, you’ll hear two sounds “lub, dub… lub, dub…, lub, dub… for each beat, that is the closing of the atrioventricular valves and then the semilunar valves.
The atriventricular valves are the two valves you can see on the furthest LEFT and RIGHT on the heart above (where the read and blue arrows are), they close first (lub) then the semilunar valves (closed in the above picture), are the two closer to the middle they close after (dub)
The two chambers on the top of the heart are the atria. They receive blood into the heart, before releasing it into the ventricles, which then pump the blood out of the heart.
Again, looking at the animation, the cambers squeeze close nicely, and in time. When a person has atrial fibrillation, the atrial fibrillate, or shake, rather than squeezing down nicely. This means that the heart no longer beats normally, so you’ll hear:
All beating randomly. That isn’t good
Whilst the til operator (atria) scans products in a nice regular fashion, the shopper (ventricles) can bag things up nicely. If however the til operator starts randomly pushing items down the til, faster than the shopper can bag them, you get a build up of shopping waiting to be bagged…
In the heart, this is a build up of blood in the atria. That isn’t good. Blood which is just sitting around not going anywhere tends to form clots – this is why we don’t bleed to death from paper-cuts not matter how much they hurt! So if you are getting blood sitting around in eddies within your heart, you are likely to be pushing little clots out to your body from the heart that is REALLY not good, as in patient having a stroke not good.
Here is where we get the crux of why atrial fibrillation matters, and by extension why the AliveCor Kardia is useful tool Atrial Fibrillation is attached to some SCARY numbers:
- 1 in 100 people in the GENERAL POPULATION in the UK are thought to have AF (1)
- Over the age of 65 that increases to 1 in 10 (As risk of AF increases with age)
- Around 20% of people with AF, have no symptoms and would not know they have it.
- If you have AF, are over 65, and in ALL OTHER WAYS ARE HEALTHY, your risk PER YEAR of a stroke is 1/166, so over 10yrs that is a 1/16 chance of having a stroke (2)
- OK, let’s add in high blood pressure to the mix (not unreasonable, 60% of people over 50yrs in the UK have hypertension) that fact alone increases the stroke risk to 1:45 per YEAR, so that is down to 1:4 over 10yrs, by the age of 70, that risk of stroke has risen to nearly 50%. Oh and a stroke from AF is in 50% of cases severely disabling. Permanently.
Those are very sobering numbers. So from my perspective as a doctor, having anyone come in saying they have palpitations, out comes the Alivecor Kardia Mobile. If they have AF I’m going to strongly advise starting blood thinners then and there whilst I run all the other tests needed in tandem to confirm the diagnosis. (That is balancing risk, yes there is a risk of bleeding due to those medications, but in most patients, that risk is still less than that of having a stroke.)
In the West, as our population ages, rates of AF will obviously increase, in turn increasing the risk of stroke, so at a simple level, I would argue (although not promote) that an AliveCor Kardia purchase is not an unreasonable consideration for anyone over the age of 60.
Medically speaking we use a formulae called CHA₂DS₂-VASc Score to calculate a persons risk of stroke. If over the age of 50, and you have more than two points on that score, as well as blood thinners, I think you could make an argument to monitor for AF in the same way that anyone with hypertension wouldn’t consider it unreasonable to monitor their blood pressure.
Atrial Fibrillation and Cyclists
Uh-oh where is he going with this?
One of the things medical school requires you to do is memorise lists. One of the earliest lists that I start to drill into my students is the causes of AF. (Seriously ignoring the AliveCor Kardia for a moment, I’m sure you are getting the message that medically speaking AF is rather important. Both from how common it is, but also how it can POTENTIALLY – such an important word when talking about subjects like this – have catastrophic effects if ignored)
Causes of AF:
- Heart Disease
- Sleep Apnoea
- Alcohol abuse
- Excess Caffeine Consumption
- That doesnt bode well for me –> Using Caffeine in Cycling
There is another factor which may potentially put people at risk of AF, but I tend not to bang on about it much at the medical school – largely due to relevance – cycling and endurance sports (BJSM 2012)
Now there is a lot to consider in this paper especially as other research, looking specifically at 2500 cyclists over 6.5yrs did not see any increase in HOSPITAL ADMISSIONS for AF
(that is a reasonable point to keep in mind, as I DONT admit many of my AF patients to hospital, so I’m going to add a grain of salt to their conclusion)
By contrast there is a lot of evidence talking about changes seen in the ECG of athletes hearts, which in a non-athlete would be considered abnormal. Ultimately the jury is still out on the long term implications of these changes which are seen in athletes hearts and whether they may be protective in the long term – I’d certainly like to think so. As a result, I for one have absolutely NO intentions of changing my the level of my sporting exertions. However that does not mean that I am blind to the possibilities of changes in the future, and think that monitoring is always going to be a good thing – which brings me neatly back to the AliveCor Kardia Mobile – rather than just referencing the device, let’s remember this a review in take a look at the kit!
AliveCor Kardia Mobile ECG and Kardia Band
To be honest there is VERY little to say about the Kardia Mobile design. You’ve a very slim device with two 1 inch square contact patches on it, with raised indents to increase the contact surface area
On the back of the unit is the device RFid tag, and the battery cover – very simple all in all.
Heck, there isn’t even that much more in the box! Simply a back plate if you want to stick the device to your phone – which may be good for many people, but doesn’t really work for me when I’m lending the unit out to patients
AliveCor Kardia Mobile ECG and Kardia Band
- ECG Channels: Single Channel
- Input Dynamic Range: 10mV
- Frequency Resp.: 0.5Hz to 40 Hz
- A/D Sampling Rate: 300 Hz
- Resolution: 16 bit
- Heart Rate Range: 30 – 300 bpm
- Battery Type: 3V Coin Cell
- Battery life: 12 months typical use
When can’t the AliveCor kit work?
What about “unclassified recordings” ie. When can’t the AliveCor kit work?
Basically if you are moving around too much – noise, motion, minimal contact with the electrodes (this can be overcome by licking your fingers, or getting your patient to do that… I MEAN LICKING THEIR OWN FINGERS NOT YOURS!!), someone else on the table, patient talking, all with result in poor readings
The Kardia Mobile is only able to provide ECG analysis between 50 and 100BPM, outside of this region, you’ll get “unclassified”. That isn’t to say that you and your heart have failed the test, but that the Kardia is unable to provide an accurate analysis outside of those parameters.
This might be something to consider from an athlete perspective, as having bradycardia or BPM <50 is not unusual, nor worrying in athletes at rest.
I tried to used the Kardia Band, both whilst on the turbo, and when collapsed in a heap on the floor after a Zwift session… Suffice to say that whilst my pulse was >100bpm in both cases, I could get absolutely no effective data from device!
AliveCor Kardia Mobile ECG – Manual
Alivecor provides a brief PDF overview about using the device. A full copy of the Alivecor Kardia Mobile manual can be found HERE
AliveCor Kardia Mobile ECG – Using the Product
The first thing to do with the Alivecor Kardia Mobile is to download the Kardia app, as this is really where the smart stuff is. Perhaps as an indicator as to how easy the Kardia Mobile is to use, the hardest part for many of the patients I have loaned the Kardia Mobile to has been getting the app onto their phone
Once you are all set up with the app, you place two fingers on each of the metal pads, the phone displays the strength of the single, and starts the 30-second recording
You get a live feed of the recording, signal strength, recording countdown, and your current heart rate. You also have the opportunity to give verbal notes – which I think is a really BAD idea, as it does affect the recording!
After the 30 second recording, you will get an analysis report
When something wrong comes up, you are provided with an alert. (Regardless of the ECG trace looking rather squiffy, the fact that the patient had a pulse of 164 at rest indicates that something odd is going on!
But what happens if you are at home, rather than in a doctors surgery when this comes up? Well you can wait to see your own GP as soon as possible (probably the best plan) or Kardia will offer to send your ECG to a clinician for a formal diagnosis
You may have noticed it says Guest for the AF, and James for mine
You can specifically record you own ECG traces, which then over time allows Kardia to build a picture, which can then be built into a report – think back to the original comment of being able to monitor things are home. Suddenly your doctor has a good record of WHAT is going on when you say you are having symptoms, but also HOW OFTEN
From this a report can be generated which can be sent to your doctor. (My report is all over the place, as I also use this device to assess patients – their names and data are never entered into the app, so things remain completely anonymous)
You can opt to download any of your ECGs to do what you will with – here is a copy of my ECG – click the image to get the whole PDF
Although perhaps more interesting is an ECG which the Kardia Mobile identified as possible atrial fibrillation – again, click the image for the full PDF. Even to someone without a medical background, you can see that the rhythm isn’t regular. The pulses are coming all over the place showing that the actual wave pattern needs to be looked at more closely to determine the issue
The app also has the ability to be a more universal form of health app, allowing you to enter other health data about yourself
A few other bits about the Kardia Mobile, which are likely of interest
The vast majority of the time, you are going to used the Kardia Mobile, as a Lead I ECG (Left hand, Right hand) – remembering that a full ECG has 12 leads, each giving a slightly different view of the heart. With the Kardia Mobile, it is also possible apply the device in two different ways to give access to a Lead II and an Anterior Pectoral Lead reading.
To get a Lead II to press the device down on your LEFT thigh, this can frequently even been done through trousers
An anterior pectoral lead can be generated by applying the Mobile to the lower LEFT side of the chest, positioned running from head to foot (Although this does make getting a connection to your phone more difficult, so works better with someone to help.
AliveCor Kardia Mobile ECG – Conclusion
Studies have documented that AliveCor Mobile ECG can accurately diagnose AF in a screening setting and the FDA approved the device for AF screening in 2014.
As discussed, AF is a significant problem with both an aging population, but potentially also with endurance athletes. Given the strong association of AF with stroke, and the significant morbidity seen from AF induced strokes screening for AF with devices like AliveCor has the real possibility of leading to early diagnosis and prevention of strokes
I’ve been using this device in the clinic for several months currently. As a medic, I have found it a terrific bit of kit, but have also found several patients who have purchased them for use with themselves and their families (normally after someone has actually seen a family member affected by AF and a stoke)
I find that the Kardia Mobile fills a nice gap between patients presenting with symptoms, and actually being able to capture the rhythm in question – which isn’t always possible until the patient has been referred for a 24hr monitor.
Should cyclist use them? Probably not. If you find you get the odd palpitation at times, certainly talk to your doctor, but if your symptoms are very infrequent, using a Kardia mobile to monitor things might not be a bad idea.
As for people who just want to know more about their body, the Kardia certainly isn’t a bad idea. But it all depends on how you view the RRP of £100, for a device which might never have any relevance to yourself – which can be looked at in the same way as a blood pressure machine, for a person who is not known to have hypertension. Sometimes, we just like to monitor ourselves.
From my perspective as a General Practice doctor, I may not use the Kardia Mobile as much as my stethoscope, but given the massive impact, and prevalence of AF, I think it is very difficult to justify NOT always carrying one in my medical bag now I know that it is available – so for me, that’s a 5* TG review!