Category Archives: Medical/Fitness Devices

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

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.