Category Archives: Medical/Fitness Devices

Kardia’s Fascinating SmartRhythm For Apple Watch Is Very Cool: Will It Allow Personal Atrial Fibrillation Detection?

The KardiaBand for Apple Watch from AliveCor has delivered on  its  unique promise of a medical grade single lead ECG recording made by placing your thumb on your wristwatch band.

The ECG recordings are equivalent in quality to those made by their previously available KardiaMobile (see my prior post here.) After more experience with the Band I think the ease of recording is superior to KardiaMobile and the ability to discriminate atrial fibrillation from normal sinus rhythm is similar to KardiaMobile.

By combining either a KardiaBand or a KardiaMobile device with Kardia’s SmartRhythm monitoring system for Apple Watch we now have the promise of personal monitoring to detect atrial fibrillation.

What is SmartRhythm?

SmartRhythm is AliveCor’s term for its system for monitoring your heart rate and activity levels in order to identify when your rhythm is abnormal.

The system “takes your heart rate and activity data gathered from the Apple Watch and evaluates it using a deep neural network to predict your heart rate pattern.”

The heart rate is obtained from the Apple Watch PPG sensor every 5 seconds.  If it differs from what is predicted SmartRhythm notifies you to record an ECG.

If you’d like to learn more detail about the development of SmartRhythm and how it functions, AliveCor has an excellent informational piece here.

You can choose to have the Kardia SmartRhythm display come up whenever your Apple Watch awakens. It’s got information on your heart rate and activity over the preceding several hours

SmartRhythm display. The light blue vertical bars representing heart rate range during an interval. The continuous lines above and below the vertical bars show the boundaries of heart rate predicted by the neural network based on your measured activity from the Watch accelerometer. . Upper left corner is yellow triangle indicating that the system detected potential abnormal rhythm and recommended a recording. The dot on the right is an ECG recording. The vertical bars at the very bottom represent steps taken during an interval

The AliveCor FAQ on SmartRhythm stresses that a notification does not always mean an abnormal rhythm. Clearly false positives can and will occur. The first day I wore my KardiaBand I had several of these.

Causes for false positives include exercise that Apple Watch couldn’t detect, stress or anxiety-in other words, situations where your heart rate is higher than predicted by how much activity you are doing.

The long term record of your SmartRhythm recordings resides on your iPhone . Here’s my record for the last week

Note that Kardia , in addition to tracking your heart rate, also shows you by the green, yellow and orange dots, the times that ECG recordings were made.

Green dots indicate recordings classified as normal and yellow as “unclassified.” In my case most of the unclassified recordings were due to heart rate >100 BPM associated with exercise.

There is one orange dot indicating that Kardia felt the ECG showed “possible atrial fibrillation.”

This happened when I took my Apple Watch off my wrist and put it on one of my patients who has permanent atrial fibrillation. I had him push on the KardiaBand sensor to make an ECG recording and it was correctly identified as atrial fibrillation.

Thus far I have had no notifications of “possible atrial fibrillation” while I have been wearing my watch thus the false positive rate appears acceptably low.

How Does SmartRhythm Perform During Exercise?

I checked out SmartRhythm’s ability to predict normal and abnormal  heart patterns by wearing it during a session on my indoor bike trainer. The device did a good job of tracking both my heart rate and activity during the workout.  You can view the most recent data by viewing your Apple Watch screen during the workout as below

Or for more detailed information you can view the complete history on your iPhone as below

The system accurately tracked my heart rate and activity (although AliveCor lists stationary bike as an activity that may result in false positives). During a session of weights after the aerobic workout despite erratic heart rates and arm movements it did not notify me of an abnormality. I also did 100 jumping jacks (which involves wildly flailing my arms) and the heart rate remained within the predicted boundaries.

What is more remarkable is that I was able while cycling at peak activity to make a  very good quality ECG recording by taking my right hand off the handle bar and pushing my thumb down on the KardiaBand sensor on my left wrist.

This recording clearly  displays p waves and is sinus tachycardia. It’s unclassified by Kardia because the rate is >100 BPM.

Afib Patient Experience

One of my patients last week, a 70 year old woman with paroxysmal atrial fibrillation, had already set up SmartRhythm monitoring on her Apple Watch.

The Apple Watch face of my patient with the Kardia icon bottom right. Note also that she has a Starbucks reward available

I have this patient like many of my afibbers utilizing KardiaMobile to check an ECG when  they think they are in afib.

However, she, like many of my afib patients, is totally unaware when her heart is out of rhythm. Such asymptomatic patients are alerted to the fact that they are in afib by detection of a rapid heart rate (from a heart rate tracking wearable or BP monitor) or an irregular heart beat (from BP monitor or by someone checking the pulse) or by a random recording of an ECG.

She’s started using SmartRhythm in the hopes that it will provide a reliable and early warning of when she goes into atrial fibrillation.

We discussed the possibility of stopping the flecainide she takes to maintain normal rhythm to test the accuracy of the SmartRhythm system for detecting atrial fibrillation in her but decided not to. She’s on an oral anticoagulant and therefore protected from stroke so development of atrial fibrillation will not be dangerous for her.

I eagerly await the first real world, real patient reports of SmartRhythm’s performance in atrial fibrillation detection.

If there are any afibbers out there who have had an episode of atrial fibrillation detected by  SmartRhythm please let me know the details.

We need such anecdotes along with controlled trials to determine how useful SmartRhythm will be as a personal wearable system for detection of afib.

Fastidiously Yours,

-ACP

N.B. I’ve copied a nice section from AliveCor’s website which describes in detail the difference between measuring heart rate from the PPG sensor that all wearable devices use versus measuring the electrical activity of the heart with an ECG.

To understand how Kardia for Apple Watch works, let’s start by talking about your heart, how the Apple Watch and other wearable devices can measure your heart rate, and how an ECG is different from the information you get from a heart rate sensor alone.

Your heart is a pump. With each beat of your heart, blood is pumped through your arteries and causes them to expand. In the time between beats, your arteries relax again. On the underside of the Apple Watch is a sensor, called a photoplethysmogram (PPG), that uses green and infrared LEDs to shine light onto your skin, and detects the small changes in the amount of light reflected back as your arteries expand and relax with each beat of your heart. Using this sensor, the Apple Watch can tell how fast your heart is beating, and how your heart rate changes over time.

But, your heart rate does not tell everything there is to know about your heart. The PPG sensor on the Apple Watch can only see what happens after each heartbeat, as blood is pumped around your body. It can’t tell you anything about what is making your heart beat, or about what happens inside your heart during each beat. An ECG is very different, and tells you a lot more!

Three hearts showing a P-Wave, QRS-Complex, and a T-Wave

An ECG measures the electrical activity in your heart muscles. It detects the small pulse of electricity from the sinoatrial node (the body’s natural pacemaker, which normally initiates each heartbeat) and the large electrical impulses produced as the lower chambers of the heart (the ventricles) contract and relax. By looking at an ECG, a doctor can discern a wealth of information about the health and activity of your heart muscle, much more than you can tell from your heart rate alone. ECGs are the required gold standard for diagnosis of arrhythmias and many cardiac abnormalities, and can even be used to see evidence of acute heart attacks and even events that have occurred in the past.

Research has shown that taking frequent ECGs increases the likelihood of detecting certain arrhythmias, and decreases the mean time to diagnosis.

Review of Kardia Band Mobile ECG for Apple Watch

The skeptical cardiologist has been evaluating the Kardia Band from AliveCor which allows one to record single lead medical grade ECGS on your Apple Watch. What follows is my initial experience with setting up the device and using it to make recordings.

After ordering my Kardia Band for Apple Watch on 11/30  from AliveCor the device appeared on my door step 2 days later on a Saturday giving me most of a Sunday to evaluate it.

What’s In The Box

Inside the box I found one small and one large black rubber wrist watch band

The larger one had had a small squarish silver metallic sensor and the smaller one had a space to insert a sensor. It turns out my wrist required the smaller band and it was very easy to pop out the sensor and pop it into the smaller band.

After replacing my current band with the Kardia band (requires pushing the button just below the band and sliding the old band out then sliding the new one in) I was ready to go.

The Eternal  fiancée did not complain about the appearance of the band so I’m taking that to mean it passes the sufficiently stylish test. She did inquire as to different colors but it appears AliveCor only has one style and one color to choose from right now.

I have had problems with rashes developing with Apple’s rubbery band and switched to a different one but thus far the Kardia band is not causing wrist irritation.

Set UP

I didn’t encounter any directions in the box or online so I clicked on the Kardia app on the watch and the following distressing message appeared.

Prior to 11/30 Kardia Band only worked in certain countries in Europe so I suspected my AliveCor app needed to be updated.

I redownloaded the Kardia app from the Apple App Store , deleted it off my Watch and reinstalled it.

I was thrilled when the app opened up and gave me the following message

However, I was a little puzzled as I was not aware that setting up Smart Rhythm was a requirement to utilize the ECG recording aspect of Kardia Band. Since I have been granted a grandfathered Premium membership by AliveCor I knew that I would have access to Smart Rhythm and went through the process of entering my name and email into the Kardia app to get this started.

Alas, when the Watch Kardia app was accessed after this I continued to get the same screen. Clicking on “need help” revealed the following message:

Bluetooth was clearly on and several attempts to restart both the watch and the iPhone app did not advance the situation.

I sent out pleas for assistance to AliveCor.

At this point the Eternal Fiancee had awoken and we went to Sardella for a delightful brunch . I had this marvelous item:

Eggs Benedict Raviolo, Mortadella, Bread Ricotta, Egg Yolk, Brown Butter Hollandaise, Potatoes 15.
 Later on that day I returned to my Kardia Band iPhone and deinstalled, reinstalled , reloaded and restarted everything.
The First Recording
At this point it worked and I was able to obtain my first recording by pushing the record ECG button and holding my thumb on the sensor for 30 seconds.
I’ve made lots of recordings since then and they are good quality and have accurately recognized that I am in normal sinus rhythm.
The Smart Rhythm component has also been working. Here is a screen shot of today’s graph.
You’l notice that the Smart Rhythm AI gave me a warning sometime in the morning (which I missed) as it felt my rhythm was abnormal. I missed making the recording but am certain that I was not in afib.
Comparison of the Kardia Band recording (on the right) versus the separate Kardia device recording (on left)  shows that they are very similar in terms of the voltage or height of the p waves, QRS complexes and T waves. 
I felt a palpitation earlier and was able to quickly activate the Kardia Watch app and make a recording which revealed a PVC.
 In summary, after some difficulty getting the app to work I am very pleased with the ease of recording, the quality of the recording and the overall performance of Kardia Band. The difficulties I encountered might reflect an early adoption issue which may already be resolved. Please give me feedback on how the device set up worked for you.
I’ll be testing this out on patients with atrial fibrillation and report on how it works in various situations in future posts.
After more experience with the Smart Rhythm monitoring system which I think could be a fantastic breakthrough in personal health monitoring I’ll give a detailed analysis of that feature.
Everwatchingly Yours,
-ACP

AliveCor’s Kardia Band Is Now Available: Mobile ECG On Your Apple Watch

AliveCor has finally gotten approval from the FDA to release its Kardia Band in the United States.

The skeptical cardiologist is quite excited to get his hands (or wrist) on one and just gave AliveCor $199 to get it.

The device incorporates a mobile ECG sensor into a wrist band that works with either 42 or 38 mm Apple watches. I’ve written extensively about AliveCor’s previous mobile ECG product (here and here) which does a good job of recording a single lead ECG rhythm strip and identifying atrial fibrillation versus normal rhythm,

Hopefully, the Kardia Band will work as well as the earlier device in accurately detecting atrial fibrillation.

According to this brief video to make a recording you tap the watch screen then put your thumb on the sensor on the band.

The app can monitor your heart rate constantly and alerts you  to make a recording if it thinks you have an abnormal rhythm.

I was alerted to the release of Kardia by Larry Husten’s excellent Cardio Brief blog and in his post he indicates that the alert service , termed Smart Rhythm,  requires a subscription of $99 per year.:

AliveCor simultaneously announced the introduction of SmartRhythm, a program for the Apple Watch that monitors the watch’s heart rate and activity sensors and provides real-time alerts to users to capture an ECG with the Kardia Band. The program, according to an AliveCor spokesperson, “leverages sophisticated artificial intelligence to detect when a user’s heart rate and physical activity are out of sync, and prompts users to take an EKG in case it’s signaling possible abnormalities like AFib.”

The Kardia Band will sell for $199. This includes the ability to record unlimited ECGs and to email the readings to anyone. The SmartRhythm program will be part of the company’s KardiaGuard membership, which costs $99 a year. KardiaGuard stores ECG recordings in the cloud and provides monthly summary reports on ECGs and other readings taken.

AliveCor tells me my Kardia Band will be shipped in 1-2 days and I hope to be able to give my evaluation of it before Christmas.

Please note that I paid for the device myself in order to avoid any bias that could be introduced by receiving largesse from AliveCor.

Proarrhythmically Yours

-ACP

N.B. Larry Husten’s article includes some perspective and warnings from two cardiologist and can be read here.

Another article on the Kardia Band release suggests that the Smart Rhythm program at $99/ year is a requirement.

Perhaps, AliveCor’s David Albert can weigh in on whether the annual subscription is a requirement for making recordings or just allows the continuous monitoring aspect.

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

AfibAlert Versus AliveCor/Kardia: Which Mobile ECG Device Is Best At Accurately Identifying Atrial Fibrillation?

The skeptical cardiologist has been testing the comparative accuracy of two hand-held mobile ECG devices in his office over the last month. I’ve written extensively about my experience with the AliveCor/Kardia (ACK) device here and here. Most recently I described my experience with the Afib Alert (AA) device here.

Over several days I had my office patients utilize both devices to record their cardiac rhythm and I compared the device diagnosis to the patient’s true cardiac rhythm.

Normal/Normal

In 14 patients both devices correctly identified normal sinus rhythm. AFA does this by displaying a green check mark , ACK by displaying the actual recording on a smartphone screen along with the word Normal.

The AFA ECG can subsequently uploaded via USB connection to a PC and reviewed in PDF format. The ACK PDF can be viewed instantaneously and saved or emailed as PDF.

 

Normal by AFA/Unreadable or Unclassified by AliveCor

In 5 patients in normal rhythm (NSR) , AFA correctly identified the rhythm but ACK was either unreadable (3) or unclassified (2). In the not infrequent case of a poor ACK tracing I will spend extra time adjusting the patient’s hand position on the electrodes or stabilizing the hands. With AFA this is rarely necessary.

In this 70 year old man the AFA device recording was very good and the device immediately identified the rhythm as normal.

Chaput AFA SR

ACK recording was good quality but its algorithm could not classify the rhythm.

GC Unclassified

A 68 year old man who had had bypass surgery and aortic valve replacement had a very good quality AFA recording with correct classification as NSRChaput AFA SR

AliveCor/Kardia recordings on the same patient despite considerable and prolonged efforts to improve the recording were poor and were classified as “unreadable”

Scott AC unreadable
Alivecor tracing shows wildly varying baseline with poor definition of p wave

 

False Positives

There were 3 cases were AFA diagnosed atrial fibrillation (AF) and the rhythm was not AF. These are considered false positives and can lead to unncessary concern when the device is being used by patients at home. In 2 of these ACK was unreadable or unclassified and in one ACK also diagnosed AF.

A 90 year old woman with right bundle branch block (RBBBin NSR was classified by AFA as being in AF.

VA AFA read as AF
Slight irregularity of rhythm combined with a wider than normal QRS from right bundle branch block and poor recording of p waves likely caused AFA to call this afib
VA unclassified RBBB
AliveCor tracing calls this unclassified. The algorithm does not attempt to classify patients like this with widened QRS complexes due to bundle branch block.

The ACK algorithm is clearly more conservative than AA. The ACK manual states:

If you have been diagnosed with a condition that affects the shape of your EKG (e.g., intraventricular conduction delay, left or right bundle branch block,Wolff-Parkinson-White Syndrome, etc.), experience a large number of premature ventricular or atrial contractions (PVC and PAC), are experiencing an arrhythmia, or took a poor quality recording it is unlikely that you will be notified that your EKG is normal.

 

One man’s rhythm confounded both AFA and AC. This gentleman has had atrial flutter in the past and records at home his rhythm daily using his own AliveCor device which he uses in conjunction with an iPad.IMG_8399.jpg

During our office visits we review the recordings he has made. He was quite bothered by the fact that he had several that were identified by Alivecor as AF but in fact were normal.

Screen Shot 2017-05-06 at 11.48.47 AM
These are recordings Lawrence made at home that i can pull up on my computer. He makes a daily recording which he repeats if he is diagnosed with atrial fibrillation. In the two cases above of AF a repeat measurement was read as normal. Of the two cases which were unclassified , one was normal with APCs and the other was actually atrial flutter

A recording he made on May 2nd at 845 pm was read as unclassified but with a heart rate of 149 BPM. The rhythm is actually atrial flutter with 2:1 block.

Screen Shot 2017-05-06 at 11.47.37 AM

Sure enough, when I recorded his rhythm with ACK although NSR (with APCS) it was read as unclassified

Screen Shot 2017-05-06 at 11.49.49 AM

AFA classified Lawrence’s rhythm as AF when it was in fact normal sinus with APCs.

AFA Mcgill AF

 

 

One patient a 50 year old woman who has a chronic sinus tachycardia and typically has a heart rate in the 130s, both devices failed.

We could have anticipated that AC would make her unclassified due to a HR over 100 worse than unclassified the tracing obtained on her by AC (on the right)was terrible and unreadable until the last few seconds. On the other hand the AFA tracing was rock solid throughout and clearly shows p waves and a regular tachycardia. For unclear reasons, however the AFA device diagnosed this as AF.

 

 

Accuracy in Patients In Atrial Fibrillation

In 2/4 patients with AF, both devices correctly classified the rhythm..

In one patient AFA correctly diagnosed AF whereas ACK called it unclassified.

This patient was in afib with HR over 100. AFA correctly identified it whereas ACK called in unclassified. The AC was noisy in the beginning but towards the end one can clearly diagnose AFScreen Shot 2017-05-06 at 8.39.06 AMScreen Shot 2017-05-06 at 8.11.53 AM

In one 90 year old man AFA could not make the diagnosis (yellow)

Screen Shot 2017-05-06 at 11.35.40 AM

ACK correctly identified the rhythm as AF

Screen Shot 2017-05-06 at 11.37.51 AM

One patient who I had recently cardioverted from AF was the only false positive ACK. AliveCor tracing is poor quality and was called AF whereas AFA correctly identified NSR>

Screen Shot 2017-05-06 at 8.42.46 AMScreen Shot 2017-05-06 at 8.42.26 AM

 

 

Overall Accuracy

The sensitivity of both devices for detecting atrial fibrillation was 75%.

The specificity of AFA was 86% and that of ACK was 88%.

ACK was unreadable or unclassified 5/26 times or 19% of the time.

 

The sensitivity and specificity I’m reporting is less than reported in other studies but I think it represents more real world experience with these types of devices.

Summary

In a head to head comparison of AFA and ACK mobile ECG devices I found

-Recordings using AfibAlert are usually superior in quality to AliveCor tracings with a minimum of need for adjustment of hand position and instruction.

-This superiority of ease of use and quality mean almost all AfibAlert tracings are interpreted whereas 19% of AliveCor tracings are either unclassified or unreadable.

-Sensitivity is similar. Both devices are highly likely to properly detect and identify atrial fibrillation when it occurs.

-AliveCor specificity is superior to AfibAlert. This means less cases that are not AF will be classified as AF by AliveCor compared to AfibAlert. This is due to a more conservative algorithm in AliveCor which rejects wide QRS complexes, frequent extra-systoles.

Both companies are actively tweaking their algorithms and software to improve real world accuracy and improve user experience but what I report reflects what a patient at home or a physician in office can reasonably expect from these devices right now.

-ACP

QardioArm: Stylish, Accurate and Portable. Is It the iPhone of Home Blood Pressure Monitors?

The skeptical cardiologist frequently has his hypertensive patients check their BPs at home and report the values to him.

An easy, accurate and efficient way to record BPs at home, and transmit to the doctor, is my Holy Grail for management of hypertension; QardioArm offers to improve on this process compared to more conventional home BP cuffs.

I recently bought a QardioArm for my father and tested one myself over the last month, and herein are my findings. I compared it closely to my prior “go to”  BP device, the Omron 10 (which I recommended as a Christmas gift here).

Appearance

The QardioArm looks like and is packaged like an Apple product. The box containing the device is esthetically pleasing, and can serve as an excellent storage and transportation mechanism. The case closes magnetically and has a pocket, within which resides the manual.

 

Upon removing the QardioArm, one is struck by how compact, sleek and cool it looks. This is not your father’s BP cuff. There are no wires or tubes coming off it, and the cuff wraps around a red (white, blue or gold) plastic rectangular cuboid.

The cuff/cuboid is small enough to easily fit in a purse or satchel, facilitating portability.

Ease of Use

Once you understand how the device works it is a breeze to use.  However, if you are inclined, like me, to skip reading the instruction manual, you run the risk of being incredibly frustrated.

First, you must download the free Qardio App to your smartphone, create a user login, register and create your personal account. If you don’t have a smartphone or tablet or don’t use the internet, this cuff if not for you. For me, this was a simple, quick process.

After setting up the Qardio App, you pair the QardioArm with the App. This requires the QardioArm be on and Blue Tooth be enabled on your smartphone.

An example of the profoundly negative review individuals give the device when they have not figured out the on/off process. This one on Consumer Reports

You might think that turning on the QardioArm, and knowing it is on,
would be an incredibly easy and obvious process: it is not (unless you pay close attention to the instructions). If you read reviews of Qardioarm on Consumer Reports or Amazon, you will encounter many very unhappy users. This is primarily because some folks could not get it to turn on.


Here are my detailed instructions for turning it on:

  1. There is a small magnet inside the cuff.
  2. The device turns itself on when you unwrap the cuff and it turns off when you wrap the cuff back up. (I am not good at wrapping things up properly and ran into issues initially because of this). When you wrap the cuff up properly you can feel the magnet locking into place and thus turning the device off.
  3. When the device is on there is no light to indicate it is on. A green light flashes on the side when it turns on, but then goes out. Many user reviews indicate frustration with this and often they end up trying to change the batteries, believing that the device is dead. I went through this same thought process initially.
  4. The device turns off “after a few minutes” if not used. You won’t know if it is on or off. If it doesn’t respond when you trigger it from the App, you must carefully rewrap the cuff and then unwrap it. If you don’t trigger the device properly with the magnet, it won’t wake up.

The QardioArm encircling the beautiful arm of the eternal fiancee’ of the skeptical cardiologist. Note: when the cuff is wrapped around my unattractive arm, it fastens properly and does not hang down.

Now that you know how to turn the device on and have paired it with your Cardio App, put the cuff over your upper arm with the cuboid over the inner aspect of your arm,
hit the big green START button and sit back while the cuff is magically inflated and an oscillometric measurement of your blood pressure performed.

 

 

The blood pressure is displayed on the app instantaneously along with pulse. If the device detects irregularity of the pulse (a possible but not reliable sign of atrial fibrillation or other abnormal heart rhythms), it display an “irregular heart beat” warning.

You can have the QardioArm take 3 BPs, a variable amount of time apart, and average the readings.

BP and pulse data can be viewed in tabular or graphic formats and  can be synched with the Apple Health App:

 

Accuracy

I found the QardioArm BP measurements to be very accurate. My medical assistant, Jenny, recorded our patient’s BPs using the “gold-standard” manual technique, and with QardioArm (consecutively and in the same arm), and there was excellent agreement. In one man with a very large arm, she could not record a BP (QardioArm’s cuff fits the arm of most people, and is appropriate for use by adults with an upper arm size between 22 and 37 cm (8.7 and 14.6 inches).  If your upper arm is larger than that, this device is not for you.  In one patient who was in atrial fibrillation, the device properly recorded an “irregular heart beat.”

From the Qardio website:

QardioArm is a highly accurate blood pressure monitor and has undergone independent, formal clinical validation according to ANSI/AAMI/ISO 81060-1:2007, ANSI/AAMI/ISO 81060-2:2009, ANSI/AAMI/IEC 80601-2-30:2009, as well as British Standard EN 1060-4:2004.

QardioArm is a regulated medical device: FDA cleared, European CE marked and Canadian CE marked.

It measures blood pressure with a resolution of 1 mmHg and pulse with 1 beat/min.

The accuracy is +/- 3 mmHg or 2% of readout value for blood pressure, and +/- 5% of readout value for pulse.

Comparison To Omron 10

I spent time evaluating the accuracy of QardioArm because a few online reviewers suggest that it is highly inaccurate for them and Consumer Reports gives it a “poor” rating for accuracy.

Consumer Reports gave the QardioArm an astonishingly low score giving it lower marks than the Omron for Convenience, Accuracy and Comfort. It gave the QardioArm a Poor mark for accuracy. No details of their measurement data are available on the site.

I compared it to the Omron 10 (Consumer Reports highest-rated BP device), and found close agreement between the two.

Simultaneous BP using Omron (above) and QardioArm (left)


I took my own BP with the QardioArm on the left arm and the Omron 10 on the right arm. Multiple simultaneous measurements showed less than 3 mmHg difference in systolic blood pressure between the two.

Unlike Consumer Reports, I found QardioArm superior to the Omron 10 in several areas:

  1. QardioArm is faster. It took 30 seconds to complete a BP measurement, compared to 50 seconds for the Omron 10.
  2. BPs are immediately available on my iPhone with QardioArm, whereas a separate Bluetooth synching process is required for the Omron App. This process never works well for me, as the Omron fails to transmit measurements reliably.
  3. It is amazingly easy to transmit BPs via email to your doctor (or friends if so inclined).

Support

I found the QardioArm website to be very informative and helpful. The manual that comes with the device is very complete and you should definitely read it before using the device. I did not need telephone or email support services, so I can’t comment on those.

Overall Rating and a Caveat

Despite an initial frustration with QardioArm, I ended up really liking this device a lot. This sounds a little silly but the QardioArm improved the esthetic experience of home BP monitoring for me. Because it is compact, sleek and attractive, patients may be more likely to utilize it on a regular basis. In particular, I see it as something that you would be much more inclined to take with you for BP monitoring at work or on vacation.

I will be recommending  this to my tech-savvy, style-conscious patients who require home BP monitoring. Previously, this type of patient would bring in their smartphone and show me the accumulated data from their BP readings. With a QardioArm, they can easily email my office the data and we can have it scanned into their record.

My final caveat: the QardioArm I gave my father for his 91st birthday does not work on his arm. It works without a problem on the arms of his friends and relatives. I have no idea why, but fortunately QardioArm honored their 30 day 100% money-back no questions asked guarantee. I’ve asked him to give me his nonagenarian perspective on the QardioArm experience so I can share it in a future post.


Quriously Yours,

-ACP

How Well Does The AfibAlert Remote Hand-Held Automatic ECG Device Work For Detection of Atrial Fibrillation?

I’ve been evaluating the ability of a mobile hand-held ECG device called AfibAlert to detect atrial fibrillation for the last few weeks.

I found that the device made very reliable and consistent recordings of cardiac rhythm and did a reasonably good job of detecting atrial fibrillation (afib).

The device  came in a plastic case with a USB cable for uploading recordings and two metal bracelets which attach to electrodes and provide an alternative recording method.

The device itself is about 6 by 3 by 1 inch.

 

Recordings are made by placing your thumbs on the silver/siver chloride electrodes

After a few seconds the display in the center will give heart rate and after 45 seconds the
device will make a decision about your rhythm:

If it diagnoses normal sinus rhythm a green check appears and if it diagnoses  afib a red telephone appears.

If it is confused you get yellow circular arrows.

As the maker of the device explains:

Lohman Technologies’ patented algorithm analyzes the patient’s heartbeat and the appropriate icon illuminates to show what action is needed. AfibAlert’s® algorithm was validated against 51,000+ ECG strips from the MIT-BIH Atrial Fibrillation Database with known diagnosis. The Afib monitor’s results were excellent, with 94.6% accuracy in detecting the presence of arrhythmias. Each recording produces a 45-second diagnostic quality ECG rhythm strip

The device I tested does not allow you to immediately see the ECG tracing. The recordings are uploaded to a PC via USB cable and then can be viewed as a PDF document.

I made 17  recordings on patients in my office one day. The age range was 50 to 93 years and most  patients were able to rapidly and easily  grasp the device with thumbs appropriately positioned to make interpretable recordings.

Only 2/17  came back. yellow. In both cases, I repeated the recording and the device was able to make the correct diagnosis. Twice I got the yellow signal on an elderly, partially blind patient who had trouble keeping his thumb on the electrode.

In 15  cases of normal sinus rhythm the device correctly identified NSR.

In one case of atrial fibrillation the device correctly identified atrial fibrillation.

 

 

In one case of SR with
APCs the device
incorrectly identified afib

 

Overall the device correctly classified 88% of the tracings. This was superior to the device I normally utilize ( AliveCor/Kardia mobile ECG)  in head to head comparison (I’ll present this comparison in a subsequent post).

My bullet points on the AfibAlert device:

-5 stars for Ease of Recording

-5 stars for Quality of recording

In all cases that uploaded, the recordings were very clear and free of artifact. The device did not upload yellow signal events and I presume more artifact is present in these recordings.

-2 stars for Convenience.

I found the software and uploading to be very awkward and slow. The company indicates new software soon to be released along with the ability to interface directly with iPads or smartphones that hopefully will improve this factor.

The inability to instantaneously view the ECG tracings means I cannot use it in my office to screen patients for arrhythmias. However, if a patient is solely using it to determine if afib is present or absent, this information is available right away.

-3 stars for Accuracy.

It does a reasonable job of identifying the patient who is in normal rhythm versus one in atrial fibrillation.

However, like AliveCor and other devices which strictly look at the variability of the pulse, it can be easily fooled by premature beats, especially when they are frequent, and inappropriately classify these as afib resulting in false positives.

In addition, when afib rates are very slow and thus much less variable it is likely AfibAlert will incorrectly classify them as normal thus resulting in false negatives.

False Negatives and False Positives

False negatives result in delayed diagnosis of afib. Patients will be falsely reassured that their rhythm is normal when it is not.

False  positives result in needless anxiety and testing/treatment.

If afib monitoring devices are to be successful they have to have a very low frequency of both types of inaccuracy.

The solution to inaccuracy of interpretation, of course, is to have a cardiologist over-read the tracings.

AfibAlert recordings are available online for review by your personal physician after being uploaded. This requires your physician to have an account with AfibAlert. There is no capability for having the recordings over read by an online cardiologist for a charge.

As far as I can tell the device is only available for purchase in the US and only on the AfibAlert website.

Interestingly, you cannot purchase AfibAlert  without a prescription from a physician.

Why this is mandated for AfibAlert and not AliveCor is a mystery to me.

 

 

Alertly Yours,

-ACP

 

 

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

 

 

 

 

Do NOT Rely on AF Detect Smartphone App To Diagnose Atrial fibrillation

I’m writing this brief post as a warning to any individuals who have purchased the  smartphone app AF Detect (screen shot below from Apple app store.) It is not a reliable detector of atrial fibrillation (AF).

screen-shot-2017-02-19-at-11-25-56-am

 

A patient of mine with AF recently  purchased this app unbeknownst to me. He  relied on its faulty information which  reassured hm he was not in AF when in fact he was in AF. Such misinformation has the potential to lead to dangerous delays in diagnosis.

There are multiple reviews on the Apple and Google app sites which confirm the total lack of reliability of this app to diagnose AF with screen-shot-2017-02-19-at-9-18-10-ammultiple instances of both failure to detect known AF and inappropriate diagnosis of AF when rhythm was not AF.

In the description of the app the company says the app will “transform you rmobile device into a personal heart rate monitor and atrial fibrillation detector”.

However after purchasing the app and before using it you see this disclaimer which img_8348states it is not to be used for any medical diagnosis.

 

 

 

 

 

 

I will be performing a more detailed analysis of this app’s performance in the future and contacting the FDA about the danger such inaccurate medical testing confers on victims.

In the meantime if you have any experience with this app or other apps claiming to detect AF reliably using detection of the pulse from finger application to the camera lens please share them with me (via email  DRP@theskepticalcardiologist.com or via comments below.)

-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