Tag Archives: Kardia

What Is The Cause of Low Voltage (Unreadable or Unclassified) AliveCor/Kardia Mobile ECG Recordings?

The skeptical cardiologist has had several of his readers submit stories and tracings of AliveCor Mobile ECG recordings which yield unclassified or unreadable recordings. In some cases this is due to excess noise but a lot of these tracings suffer from low voltage: the height of the tracing is very small.

John, a skepcard reader, is typical.

Recently, he noted his heart was racing and made an AliveCor recording which came back interpreted by the app as normal

EKG-3
First tracing. Note the QRS complex (the large regular spikes) are 2 boxes high. Right in front of them is a little bump, the p wave indicating normal sinus rhythm

 

Three hours later he made a second recording which has drastically lower voltage: the only deflections visible are tiny QRS complexes, the p waves have disappeared. I think this is also normal sinus rhythm but because p waves can’t be seen this came back uninterpretable and if there were any irregularity AliveCor would have called it atrial fibrillation:

EKG-4
Second tracing. Note the QRS spikes now are less than half of a box tall. There are no consistent p waves visible (unless one has a good imagination). The bumps after QRS spikes are T waves.

John has a theory on the cause of some of his low voltage recordings which I shall reveal in a subsequent post after testing it.

In the meantime, if any readers have suggestions as to causes of low voltage recordings or have noted similar issues please comment below or send recordings and observations to DRP@theskepticalcardiologist.com.

Voltagophilistically Yours,

-ACP

 

 

 

 

Sustained Atrial Fibrillation or Not: The Vagaries and Inaccuracies of AliveCor/Kardia and Computer Interpretation of ECG Rhythm

The skeptical cardiologist has often sung the praises of the AliveCor Mobile ECG for home and office heart rhythm monitoring (see  here and here.) However, there is a significant rate of failure of the device to accurately identify atrial fibrillation.  I’ve seen numerous cases where the device read afib as  “unclassified” and normal sinus rhythm (usually with PVCs or PACs) called afib both in my office and with my patient’s home monitors.

In such  cases it is easy for me to review my patient’s  recordings and clarify the rhythm for them.

For those individuals who do not have a img_8322cardiologist available to review the recordings, AliveCor offers a service which gives an option of having either a cardiac technician or cardiologist review the tracing. The “cardiac technician assessment” costs $9 and response time is one hour. The “Clinical Analysis and Report by a U.S. Board Certified Cardiologist” costs $19 with 24 hour response time.

Obviously, I have no need for this service but I’ve had several readers provide me with their anecdotal experiences with it and it hasn’t been good.

One reader who has a familial form of hypertrophic cardiomyopathy utilizes his AliveCor device to monitor for PVCs. One day he made the following recording which AliveCor could not classify:
screen-shot-2017-02-14-at-5-37-42-am
screen-shot-2017-02-14-at-5-43-51-am screen-shot-2017-02-14-at-5-41-41-am

He then requested a technician read which was interpreted as “atrial fibrillation sustained.”

He then had requested the cardiologist reading which came back as Normal Sinus Rhythm.

Finally, he againscreen-shot-2017-02-14-at-5-44-09-am requested the technician
read and got the correct reading this time which is normal sinus rhythm with PACs

When my reader protested to Kardia customer service about this marked inconsistency: three different readings in a 24 hour period, a Kardia  customer service rep responded :

 I was able to review this with our Chief Medical Officer who advised that the recording shows Sinus Rhythm with PACs. The Compumed report seldom provides identification of PACs and PVCs as most cardiologists believe they are not significant findings. The sustained AFib finding was incorrect, so I have refunded the $5 fee you had paid.

Please let us know if you have any other questions.

As I pointed out in my post on palpitations, most PVCS are benign but some are not and patients with palpitation would like to know if they are having PVCS and/or PACs when they feel palpitations.

More importantly, the misdiagnosis of afib when the rhythm is NSR with PACs or PVCs can lead to extreme anxiety.

sr-pvcs-with-annotations
This tracing clearly (to me) shows regular and similar upward deflections (red arrow, p waves) which are a similar distance from the QRS complexes which follow (QRS complexes). The green arrows point to irregular deflections due to noise which can confuse computer algorithms (and non-cardiologists.) The distance between the QRS complexes is very regular (black arrow, RR interval). Thus, this is clearly normal sinus rhythm (NSR). Later in the recording PVCs (green arrows) are noted occurring every other beat. The distance between the QRS complexes on either side of the PVC is still the same as two RR intervals. This is clearly ventricular bigeminy.

Heres a recording
I made in my office this morning on a patient with cardiomyopathy and a defibrillator.

This is very clearly NSR with PVCs yet AliveCor diagnosed it as “possible atrial fibrillation.”

The AliveCor algorithm  is not alone in  making frequent errors in the diagnosis of atrial fibrillation.

The vast majority of ECGs performed in the US come with an interpretation provided by a computerized algorithm and medical personnel rely on this interpretation until it can be verified or corrected by an overreading cardiologist.

One study demonstrated that computerized ECG interpration (ECG-C) is correct only 54% of the time when dealing with a rhythm other than sinus rhythm

Another study found that 19% of ECG-C misinterpreted normal rhythm as atrial fibrillation. Failure of the physician ordering the ECG to correct the inaccurate interpretation resulted in change in management and initiation of inappropriate treatment, including antiarrhytmic medications and anticoagulation, in 10% of patients. Additional unnecessary diagnostic testing was performed based on the misinterpreted ECGs in 24% of patients.

When lives or peace of mind are at risk you want your ECG interpreted by a cardiologist.

I would like to take this opportunity to personally issue a challenge to IBM’s Watson.

Hey, Watson, I bet $1,000 I can Interpret cardiac rhythm from an ECG with more accuracy than you can!

Are you listening, IBM?

Do you copy, Watson?

-ACP

AliveCor Mobile ECG Update: Successes and Failures

The  AliveCor/Kardia mobile ECG device is a really nifty way to monitor your heart rhythm. Since acquiring the third generation device (which sits within or on my iPhone case and communicates with a smartphone app) I have begun routinely using it  on my patients who need a heart rhythm  check during office visits. It saves us the time, inconvenience (shirt and bra removal) and expense of a full 12-lead ECG which I would normally use.

In addition, I’ve convinced  several dozen of my patients to  purchase one of these devices and they are using it regularly  to monitor their heart rhythms. Typically, I recommend it to a patient who has had atrial fibrillation (Afib)  in the past or who has intermittent spells of palpitations.

Some make daily recordings to verify that they are still in normal rhythm and others only make recordings when symptoms develop.

Once my email invitation request is accepted I can view the ECGs recorded by my patients who have AliveCor devices as I described here.

This monitoring has in many cases taken the place of expensive, obtrusive and clumsy long term event monitors.

In general, it has been very helpful but the device/app makes occasional mistakes which are significant and sometimes for certain patients it does a poor job of making a good recording.

Alivecor Success Stories

One of my patients,  a spry ninety-something year young lady makes an AliveCor recording every day, since an episode of Afib 9 months ago.

And when I say every day I mean it literally everyday. It could be because she is compulsive or perhaps she has programmed the AliveCor to remind her. When I log in to the AliveCor site and click on her name I can see  these daily recordings:Screen Shot 2016-06-17 at 12.40.07 PM

After a month of normal daily recordings, she suddenly began feeling very light headed and weak with a sensation that her heart was racing.

Screen Shot 2016-06-17 at 12.41.13 PMShe grabbed her trusty iPhone and used the AliveCor device attached to it to make a recording of her cardiac rhythm. This time, unlike the dozens of other previous recordings, the device indicated her heart rate was 157  beats per minutes , about twice as fast as usual.

After 5 hours her symptoms abated and by the time of Screen Shot 2016-06-17 at 12.46.52 PMher next recording she had gone back to the normal rhythm.

She made two other recordings during the time she felt bad and they both confirmed Afib at rates of 140 to 150 beats per minute.

In this case, the device definitely alerted her to a marked and dramatic increase in heart rate but was not capable of identifying this as Afib In my experience with several hundred recordings, the device accurately identifies atrial fibrillation about 80% of the time. On rare occasions (see here) it has misidentified normal rhythm with extra beats as atrial fibrillation

Review Options

AliveCor/kardia users  have the option of having their recordings IMG_6936-1interpreted for a fee by a cardiologist or a technician.

My patients can alert me of a recording and I can go online and read the ECG myself and then contact the patient to inform them of my interpration of their heart rhythm and my recommendations.

Another patient made the recording below:Screen Shot 2016-06-18 at 11.32.26 AMAlthough she is  at high risk of having a stroke during the times she is in Afib, we had been holding the blood thinner I had started her on because of bleeding from her mouth. I had instructed her to take daily recordings of her rhythm with the AliveCor until she was seen by her dentist to evaluate the bleeding.

In this case, the AliveCor performed appropriately, identifying correctly the presence of Afib which was the cause of her nocturnal symptoms.

AliveCor Failures

A young woman emailed me that her AliveCor device on several screen-shot-2016-11-27-at-5-18-23-amoccasions has identified her cardiac rhythm during times of a feeling of heart racing and palpitations as “possible atrial fibrillation.”  When she sent the recordings in to AliveCor to have a paid interpretation, however, the recordings were interpreted as sinus tachycardia with extra beats.  Indeed , upon my review her rhythm was not Afib. Clearly, when the device misidentifies Afib, this has the potential for creating unnecessary anxiety.

It is not uncommon for a full, 12-lead ECG done in the hospital or doctor’s office  by complex computer algorithms to misinterpret normal rhythm as Afib so I’m not surprised that this happens with AliveCor using a single lead recorded from the fingers.

The young woman was advised by AliveCor to try a few things such as using the device in airplane mode, sitting still and wetting her fingers which did not help. She was sent a new device and the problem persisted. She finds that putting the device on her chest gives a better chance of success.

She also runs into a problem I see frequently which is a totally normal recording labeled by the device as  “unclassified.”screen-shot-2016-11-27-at-5-35-05-am

In this example, although I can clearly see the p-waves indicating normal sinus rhythm, the voltage is too low for the device to recognize.

Send Me Your AliveCor Problems and Solutions

I’m interested in collecting more AliveCor/Kardia success and failure stories so please post yours in the comments or email me directly at DRP@theskeptical cardiologist.com.

In addition, I’m interested in any tips AliveCor users have to enhance the success of their recordings: What techniques do you use to make the signal strength and recording better? What situations have you found that tend to worsen the signal strength and recording quality?

Still Unclassified Yours,

-ACP

P.S. Tomorrow is Cyber Monday and I note that Kardia is running a “Black Friday” special through 11/28, offering the device at 25% off.

screen-shot-2016-11-25-at-6-00-14-amP.P.S. Kardia, You should change the statement on your website, “90% of strokes are preventable if you catch the symptoms early.”  makes no sense. I think you mean that some strokes are preventable (I have no idea where the 90% figure come from) if one can detect Afib by utilizing a monitoring device to assess symptoms such as palpitations or irregular heart beat.

 

 

Getting To The Heart Of Father’s Day

The skeptical cardiologist received an email from the folks at AliveCor a few days ago with the subject line:

Dad’s heart matters – Kardia Mobile for Dad will give you peace of mind and make Dad happy

The email contains this image of an older well-dressed man (withScreen Shot 2016-06-18 at 9.03.26 AM lots of bling) standing in a beautiful meadow near the ocean. The man has decided to turn his back on the ocean and check his heart rhythm using the AliveCor/Kardia (AliveCor has changed the name of its ECG devices to Kardia) mobile ECG. This man is a happy dad! (Unless his heart rhythm is interpreted as atrial fibrillation. Then the beach walk is ruined.)

The email asks the question “What if Dad’s heart really was an open book?”

Uhh, he’d be dead? Clearly books don’t function well at pumping 5 or 6 liters of blood through the cardiovascular system every minute whether they are open or closed. Perhaps  the question is using either  the heart or an open book as a metaphor?

The advertisement goes on to suggest that I get my dad an AliveCor device for father’s day  “So you always know what his heart is thinking.”

I believe this is the marketing person’s attempt to extend the metaphor of the open book, i.e., you know exactly what dad’s brain is thinking, now you can extend this knowledge to his heart.  The metaphor of the heart “thinking” is quite poor but poor metaphors are the norm today.

Bad metaphors and bad writing abound on father’s day because 90 million greeting cards are purchased and given as (according to the Greeting Card Association)  “a meaningful expression of personal affection for another person.” Despite the increasing use of Facebook and its ilk to transmit emotions, the Greeting Card Association assures us that “The tradition of giving greeting cards … is still being deeply ingrained in today’s youth, and this tradition will likely continue as they become adults and become responsible for managing their own important relationships.

Mobile Ecg Monitor As A Father’s Day Gift

I have to say that despite the horror of the writing in this email advertisement it got me thinking about getting my father a Kardia device. I’ve suggested  previously that  an AliveCor device would make a good gift for Christmas for a loved one who has intermittent unexplained palpitations or atrial fibrillation but had not considered this for my dad.

For one thing he does not possess a smart phone which is required to  make the Kardia device functional. For another, he doesn’t have atrial fibrillation (that we know of. Perhaps if I knew what his heart was thinking we would find out that it likes to fibrillate late at night,)

Perhaps it’s time to upgrade my Dad to an iPhone I began thinking.

But wait! He has an iPad mini (that he seems to only use for FaceTime conversations.)

Further research reveals that Kardia is not only compatible with iPhone and Android smartphones but apparently iPads and IPod Touch.Screen Shot 2016-06-19 at 8.04.27 AM

Taking Care of Dad’s Heart

What about the rest of the slick advertising copy in my email?

And now you can know the way to help take care of it. Kardia gives Dad a medical-grade EKG in only 30 seconds. It even gives him expert analysis and tracking, with reports getting shared directly with his physician

This part is pretty clear and correct. I use Kardia daily in my office to record patient’s heart rhythm and I have a dozen patients now who make recordings outside of the office. They can have their recordings read by a random cardiologist for a fee or establish a link with me as their provider and I can review them through my account for free.

 Is It The First Father’s Day Gift That Leads To More Father’s Days?

The ad ends with the remarkably brazen statement that “It’s the first Father’s Day gift that leads to more Father’s Days.”

While I find the device more helpful in many instances than current expensive and intrusive long term monitoring devices for detecting and monitoring atrial fibrillation and other abnormal heart rhythms, it is a huge leap to suggest that this translates somehow into a longer life span.

To AliveCor’s credit, despite such ridiculous marketing drivel , studies presented at the recent Heart Rhythm Society Scientific Meetings suggest:

  • Kardia Mobile Superior to Conventional Monitoring: Researchers at the Leeds General Infirmary found that the AliveCor monitor is superior to conventional Holter monitoring in patients with palpitations, providing a higher diagnostic yield, more detected arrhythmias, with a similar workload.

  • Kardia Mobile Leads to Improved Patient Compliance:Researchers at the University of Buffalo found that AliveCor provides a diagnostic yield comparable to a 30-day ambulatory looping event monitor and that the smartphone-based ECG monitor can be used as a first approach for the diagnosis of palpitations.

  • Kardia Mobile provided more information resulting in changes in arrhythmia patient management than traditional external event recorders in a study from researchers at the University of Miami.

  • AliveCor’s AF algorithm was reported to be superior by researchers at Arizona State University to the patient’s own ability to detect AF via symptoms.

    But even if these studies make it to publication they don’t suggest the device provides any improved longevity. In fact, such data, do not exist for any monitoring device.

Happy Father’s Day, Dad! Don’t be surprised when we FaceTime later today that I’ve found another use for your iPad.

Paternally Yours,

-ACP

N.B. Clearly I receive no consulting, speaking or P.R. writing fees of any kind from AliveCor. Nor do they provide me with any free devices. What’s more, when I lose one of their devices they don’t replace it.  I am totally free of any conflict of interest.

 

AliveCor Is Now Kardia and It Works Well At Identifying Atrial Fibrillation At Home And In Office

I’ve been using the AliveCor Mobile ECG App/Device to record my patients’ heart rhythm in my office for about 6 months now.

It has for the most part taken the place of the more elaborate, but cumbersome and time-consuming, 12-lead ECG in patients where heart rhythm is my only concern.

I’ve also convinced about a dozen of my patients who have intermitent atrial fibrillation to obtain the device and they are actively using it to monitor at home their heart rhythm. Through the AliveCor website, I can view their recordings and see what their heart rhythm is doing when they have symptoms.

Last week, a patient of mine (I’ll call her Suzy) who has had significant prolonged episodes of atrial fibrillation associated with heart failure (but cannot tell when she is in or out of rhythm) notified me that her device was interpreting her rhythm as atrial fibrillation. She had not had any symptoms, but was making  daily recordings for surveillance.

Suzy called our office and we brought her in the next day and confirmed with a 12-lead ECG that she was indeed in atrial fibrillation with a heart rate of 120 beats per minute.

It’s pretty amazing that this little, inexpensive device can now replace expensive and elaborate long term cardiac monitors for many of my patients.

AliveCor Rebrands Itself to Kardia


Screen Shot 2016-03-28 at 5.38.34 AM
I’ve noticed that AliveCor has rebranded itself as Kardia. If you go to http://www.alivecor.com now you see the fourth generation device along with promotion of a “Kardia band” which apparently works with an Apple Watch to record your ECG.

The Kardia band is not available for purchase at this time but if and when I can get one, it might motivate me to purchase an Apple watch.

When I purchased my AliveCor device in June, 2015 it cost $74.99 from Amazon.com. The newer version is priced at $99 at both AliveCor and Amazon websites. I’m told by Dr. David Albert of AliveCor that this “fourth generation” version is more accurate, so I have purchased it to see if it reduces the problem of occasional bad recordings.

Screen Shot 2016-03-28 at 5.38.10 AM

You can see in this picture from the website that the formerly flat metal electrodes now have bumps. Dr. Albert says these result in more surface area for better contact with skin. We will see.

The Value of Early Detection Of Atrial Fibrillation

Meanwhile, I will be doing an electrical cardioversion (shocking or resetting the heart) on Suzy to get her back to normal sinus rhythm.  If we had not detected the asymptomatic onset of her rapid atrial fibrillation using the AliveCor/Kardia device, chances are we wouldn’t have known about it until her heart muscle weakened again and she became short of breath from heart failure.

I have Suzy on blood thinners to lower her risk of stroke associated with her Afib but for my patients who are not on blood thinners, detection of silent or asymptomatic AFib is even more important.

-Affibly yours,

-ACP

p.s. The skeptician in me feels this post borders on infomercialese.

Let me make it clear that I have no connection with the company formerly known as AliveCor and have received nothing from them (not even free test devices or Apple Watch Kardia Bands!) but I’m just really excited about the device and how it can help my patients (oh, please excuse me, this really sounds like marketing) “empower” themselves to take control of their heart rhythm.

In the course of writing this, I’ve discovered an academic paper evaluating 13 ECG smart phone type ECG devices so there are other devices you could try. I haven’t had the time or resources to evaluate them.