Category Archives: mobile ECG

What Is Behind The Significant Changes In AliveCor’s Kardia Mobile ECG App?

The Skeptical Cardiologist is a strong proponent of empowering patients with atrial fibrillation by utilizing personal cardiac rhythm devices such as Afib Alert or AliveCor’s Kardia.

I’ve written about my experiences with the initial versions of the Kardia mobile ECG device and the service it provides here and here.

I have been monitoring dozens of my afib patients using AliveCor’s Physician Dashboard.

Recently AliveCor changed fundamentally the way their app works such that for new users much of the functionality I described in my previous posts now requires subscribing to their Premium service which costs $9.99 per month or $99 per year.

What Has Changed With The Kardia App

The Kardia device which works with both iOs and Android smart
phones is unchanged and still generates a “medical-grade” single lead rhythm strips which appears within the Kardia app.

Screenshot from AliveCor’s website showing the Kardia recording device being utilized with the obtained  typical ECG recording displayed on the smartphone app.

 

 

The app still is reasonably accurate at identifying atrial fibrillation or normal heart rhythms and offers a fee-based service for interpretation of unclassified ECGs.

However, for new purchasers of Kardia,  the capability to access, email or print prior ECG recordings has gone away. Prior to March of this year, Kardia users could access prior ECG tracings which were stored in the cloud  by touching the “Journal” button on the app. These older tracings could be emailed and they were available through the cloud for a physician like myself to review at any time.

Now new Kardia purchasers will find that when they make an ECG recording they have the option to email a PDF of the ECG but once they hit the DONE button it is gone and is not stored anywhere.

For my patients purchasing after March, 2017 this means that unless they  purchase Kardia Premium service I will not be able to view their ECG recordings online.

An AliveCor account executive summarized for me the changes as follows:

We added a significant number of features over the past year and a half, and grandfathered all users on March 16th, 2017. New users now have the option to download and use Kardia for free, but the premium services are $9.99/mo or $99/year. Kardia Premium allows unlimited storage and history of their EKGs, summary reports with longitudinal data, blood pressure monitoring and tracking weight and medication.

Why Journal Functionality Is Important

If you purchased your AliveCor/Kardia device prior to March 16th, 2017 ago the journal  functionality still works. Let’s call such customers “Journal Grandfathered”.

This Journal functionality is important in a number of ways:

  1. My Journal Grandfathered patients can bring their phones with them during an office visit and we can review all of their ECG tracings.
  2. Journal gGandfathered Kardia users can email their old tracings to their physicians or to anyone they wish (even the skeptical cardiologist!). They can also print them out and save PDFs of the tracings.
  3. I  can view through my online physician account all of my Journal Grandfathered patients. This means any time a patient of mine makes a recording that is unclassified or suggests atrial fibrillation I can be notified and immediately view it online.

This fundamental change took place as AliveCor attempts to convince  purchasers of the Kardia device to use their Premium service.

Why AliveCor Changed The Kardia App Function

Dr. David Albert, inventor and  cardiologist and the founder of AliveCor was kind enough to talk with me about this change.

He indicates that of the 150,000 AliveCor users, 10,000 are now using the Kardia Premium service. About 20% of new users elect Kardia Premium.

Prior to the change all AliveCor users had their old ECG recordings stored in the cloud in a HIPPA compliant fashion. This free service was costing AliveCor quite a bit and the company felt it was best to switch to a subscription service to provide this secure cloud storage.

With the change to the (relatively inexpensive)  subscription service, patients will get additional features. As the AliveCor account executive described:

Kardia Premium allows unlimited storage and history of their EKGs, summary reports with longitudinal data, blood pressure monitoring and tracking weight and medication.

 

 

I’ve looked at the Premium service and it seems quite useful when combined with a connected physician utilizing Kardia Pro.  I’ll evaluate the Premium service and the physician Kardia Pro service  further and write a full post on its features in the near future.

If you are not grandfathered and want to stick with the Basic Kardia service you still have an immensely useful and  inexpensive device which allows personal detection of your cardiac rhythm. Just remember to email yourself the ECG recording you just made before you hit DONE.

Nonarrhythmically Yours,

-ACP

AliveCor (Kardia) Has A Premature Beat Problem: How PVCs and PACs Confuse The Mobile ECG Device

The skeptical cardiologist has many patients who are successfully using their AliveCor/Kardia devices to monitor for episodes of atrial fibrillation (afib).

However, a significant number of patients who have had atrial fibrillation also have premature beats. Sometimes patients feel these premature beats as a skipping or irregularity of the heart beat. Such palpitations  can mimic the feeling patients get when they go into atrial fibrillation.

The ideal personal ECG monitor, therefore,  would be able to reliably differentiate afib from premature beats for such patients.

Premature Beats: PVCs and PACs

I’ve discussed premature ventricular contractions (PVCs) here and here.  Premature beats can also originate from the upper chambers of the heart or atria.

Such  premature atrial contractions (PACs) have generally been considered benign in the past but a recent study showed that frequent (>30 s per hour) PACs  or runs of >20 PACs in a row were associated with a doubling of stroke risk.

For patients who experience either PVCs or  PACs the AliveCor device is frequently inaccurate.

PACs Misdiagnosed As Atrial Fibrillation

Here is a panel of recordings made by a patient of mine who has had documented episodes of atrial flutter in the past and who monitors his heart rhythm with Alivecor regularly:

Of the ten recordings , four were identified as “possible atrial fibrillation.”

Unfortunately only one of the four “possible atrial fibrillation” recordings has any atrial fibrillation: this one has 7 beats of afib initially then changes to normal sinus rhythm (NSR).

The other 3 recordings identified by AliveCor as afib are actually normal sinus rhythm with premature beats.

The first 3 beats are NSR. Fourth beat is a premature beat

In addition, frequently for this patient AliveCor yields an “Unclassified” reading for NSR with PACs as in this ECG:

PVCs Misread As Atrial Fibrillation

I wrote about the first patient I identified in my office who had frequent PVCs which were misdiagnosed by AliveCor as afib here.

Since then, I’ve come across a handful of similar misdiagnoses.

One of my patients began experiences period palpitations 5 years after an ablation for atrial fibrillation. He obtained an AliveCor device to rec  ord his rhythm during episodes.

For this patient,, the AliveCor frequently diagnoses “possible atrial fibrillation” but  all of his episodes turn out not to be afib. In some cases he is having isolated PVCs:

The first 3 beats in the lower strip are NSR. The fourth beat (purpose circle) is a PVC. AliveCor interpreted this as afib

At other times he has periods of atrial bigeminy  which are also called afib by AliveCor. In this tracing he has atrial bigeminy and a PVC.

 

 

PVCs Read As Normal

Premature beats sometimes are interpreted by AliveCor as normal. A reader sent me a series of  recordings he had made when feeling his typical palpitations. all of which were called normal. Indeed, all of them but one showed NSR. However on the one below the cause of his palpitations can be seen: PVCs.

The NSR beats (blue arrows) followed at times by PVCs (red arrows))

I obtained the “Normal”  tracing below from a patient in my office with a biventricular pacemaker and frequent PVCs who had no symptoms.

Paced beats (blue arrows) PVCs (red arrows)

PVCs Read As Unclassified 

A woman who had undergone an ablation procedure to eliminate her very frequent PVCS began utilizing AliveCor to try to determine if she was having recurrent symptomatic PVCs. She became quite frustrated because AliveCor kept reading her heart rate at 42 BPM and giving her an unclassified reading.

AliveCor is always going to call rhythms (other than afib) unclassified when it counts a  heart rate less than 50 BPM or greater than 100 BPM.

In this patient’s case, every other beat was a PVC (red circles). Her PVCs are sufficiently early and with low voltage so the AliveCor algorithm cannot differentiate them from T Waves and only counts the normal sinus beats toward heart rate.

Accurate AliveCor Readings

I should point out that many of my patients get a very reliable assessment from their devices. These tracings from a woman with paroxysmal atrial fibrillation  are typical: all the Normal readings are truly normal and all the atrial fibrillation readings are truly atrial fibrillation with heart rates  above 100.

AliveCor’s Official Position on Premature Beats

The AliveCor manual states

The Normal Detector in the AliveECG app notifies you when a recording is “normal”.  This means that the heart rate is between 50 and 100 beats per minute, there are no or very few abnormal beats, and the shape, timing and duration of each beat is considered normal.

What qualifies as “very few” abnormal beats is not clear. The manual goes on to state that the AliveCor normal detector has been designed to be conservative with what it detects as normal.

What is clear is that premature beats  significantly confuse the AliveCor algorithm. Both PVCs and PACs can create a false positive diagnosis of atrial fibrillation when it is not present.

Consequently, if you have afib and premature beats you cannot be entirely confident that a reading of afib is truly afib. Strongly consider having the tracing reviewed by a cardiologist before concluding that you had afib.

On the other hand if you are experiencing palpitations and make a recording with Alivecor that comes back as normal do not assume that your heart rhythm was totally normal. While highly unlikely to be afib, your palpitations could still be due to PACs or PVCs.

If a patient of mine has an abnormal or questionable AliveCor recording it is currently a very simple process for me to review the recording online  through my AliveCor doctor dashboard. The recordings can also be emailed to me.

However, Kardia appears to be trying to move new AliveCor purchasers to a subscription or Premium service. In addition, Kardia keep giving me messages that “the doctor dashboard is going away.”

Coralively Yours,

-ACP