My first patient this morning, a delightful tech-savvy septagenarian with persistent atrial fibrillation told me she had been monitoring her rhythm for the last few days using her Apple Watch 4’s built in ECG device.
I had been eagerly awaiting Apple’s roll out since I purchased the AW4 in September (see here) and between patients this morning I down-loaded and installed the required iPhone and Watch upgrades and began making AW4 recordings.
Through the day I tried the AW4 and the Kardia on patients in my office.
Apple Watch 4 ECG Is Easy and Straightforward
The AW4 ECG recording process is very easy and straightforward. Upon opening the watch app you are prompted to open the health app on your iPhone to allow connection to the Watch ECG information. After this, to initiate a recording simply open the Watch ECG app and hold your finger on the crown.
Immediately a red ECG tracing begins along with a 30 second countdown.
Helpful advice to pass the time appears below the timer:
“Try Not to move your arms.”
“Apple Watch never checks for heart attacks.”
When finished you will see what I and my patient (who mostly stays in sinus rhythm with the aid of flecainide) saw-a declaration of normality:
Later in the day I had a few patients with permanent atrial fibrillation put on my watch.
This seventy-something farmer from Bowling Green, Missouri was easily able to make a very good ECG recording with minimal instruction
The AW4 nailed the diagnosis as atrial fibrillation.
We also recorded a Kardia device ECG on him and with a little more instruction the device also diagnosed atrial fibrillation
After you’ve made an AW4 recording you can view the PDF of the ECG in the Health app on your iPhone where all of your ECGs are stored. The PDF can be exported to email (to your doctor) or other apps.
Apple Watch Often “Inconclusive”
The AW4 could not diagnose another patient with permanent atrial fibrillation and judged the recording “inconclusive”
The Kardia device and algorithm despite a fairly noisy tracing was able to correctly diagnose atrial fibrillation in this same patient.
I put the AW4 on Sandy, our outstanding echo tech at Winghaven who is known to have a left bundle branch block but remains in normal rhythm and obtained this inconclusive report .
Kardia, on the other hand got the diagnosis correctly:
One Bizarre Tracing by the AW4
In another patient , an 87 year old lady with a totally normal recording by the Kardia device, the AW4 yielded a bizarre tracing which resembled ventricular tachycardia:
Despite adjustments to her finger position and watch position, I could not obtain a reasonble tracing with the AW4.
The Kardia tracing is fine, no artifact whatsoever.
What can we conclude after today’s adventures with the Apple Watch ECG?
This is an amazingly easy, convenient and straightforward method for recording a single channel ECG.
I love the idea that I can record an ECG whereverI am with minimal fuss. Since I wear my AW4 almost all the time I don’t have to think about bringing a device with me (although for a while I had the Kardia attached to iPhone case that ultimately became cumbersome.)
Based on my limited sample size today, however, the AW4 has a high rate of being uncertain about diagnoses. Only 2/3 cases of permanent atrial fibrillation were identified (compared to 3/3 for the Kardia) and only 4/6 cases of sinus rhythm were identified.
If those numbers hold up with larger numbers, the AW4 is inferior to the Kardia ECG device.
I’d rather see the AW4 declare inconclusive than to declare atrial fibrillation when it’s not present but this lack of certainty detracts from its value.
What caused the bizarre artifact and inconclusive AW4 tracing in my patient is unclear. If anybody has an answer, let me know.
We definitely need more data and more studies on the overall sensitivity and specificity of the AW4 and hopefully these will be rapidly forthcoming.
For most of my patients the advantages of the AW4 (assuming they don’t already have one) will be outweighed by its much greater cost and we will continue to primarily utilize the Kardia device which will also allow me to view all of their recordings instantaneously in the cloud.
Note. The original version of this post had the wrong ECG tracing for the first “inconclusive” AW4 recording of a patient with permanent atrial fibrillation. H/t to discerning reader Vignesh for pointing this out months after the initial posting.
One of my patients has been on the cutting edge of personal cardiac monitoring devices and I asked him to share his recent experience with the QardioCore ECG strap. What he sent me is a fascinating description of how the device works (which is unique in this area) along with how it was crucial in diagnosing the cause of his recent symptoms. I’m sharing it below.
“QardioCore is a clinical-quality wearable electrocardiogram recorder. An electrocardiogram – often abbreviated as ECG or EKG – is a test that measures the electrical activity of the heart. With each heart beat, an electrical impulse (or “wave”) travels through the heart. This wave causes the muscle to squeeze and pump blood from the heart.
An ECG gives two major kinds of information. First, by measuring time intervals on the ECG, a doctor can determine how long the electrical wave takes to pass through the heart. Finding out how long the wave takes to travel from one part of the heart to the next shows if the electrical activity is normal or slow, fast or irregular. Second, by measuring the amount of electrical activity passing through the heart muscle, a cardiologist may be able to find out if parts of the heart are too large or are overworked. During an ECG, several sensors, called electrodes, capture the electrical activity of the heart.
QardioCore is ideal for health conscious individuals or those with known or suspected heart conditions to record their everyday ECGs, physical activity, sport performance and medical symptoms and share their data with their doctors. Medical professionals can use QardioCore to quickly assess heart rate and rhythm, screen for arrhythmias, and remotely monitor and manage patients who use QardioCore.
QardioCore should be only used in conjunction with professional medical advice, diagnosis, or treatment, and not as a substitute, or a replacement for it. Qardio creates products and services that conform to US quality, safety and security requirements for medical products, while delivering a modern user experience. QardioCore will begin selling in the US after receiving US Food and Drug Administration clearance.”
Unfortunately, the US FDA tends to move slowly, and we can only speculate as too why, but the device is not available for purchase here. However, I found a friend in France who purchased one for me and shipped me the device. It is not illegal for me to use the device here, but it is not allowed to be sold here in the US.
I use an Apple I-Phone 8Plus and have used both the AliveCor KardiaBand and the KardiaMobile found here (https://store.alivecor.com), and reviewed by the esteemed Skeptical Cardiologist in other posts as well. While I find it as a useful tool, my only dissatisfaction is that I want to passively monitor my heart during sporting activities and look for rhythm disturbances. While I’m no expert in either sporting activities or rhythm disturbances, I’ve completed some healthy reading and living on both subjects and have a general awareness of the topic.
The QardioCore device is simple to wear, comes with three belts that can be used and cleaned, and comes with a charging cable. Everything that the app, and the product does, seems to be accurately described on their web site, so I won’t cover off on details here. You can read more about it at this link: https://www.getqardio.com/qardioapp/My only dissatisfaction with this device, and other blue tooth devices, has nothing to do with the device itself. Apple seems to randomly disconnect from Bluetooth devices with their phones. I don’t pretend to know the specific mechanisms for the problem, but my blue tooth devices for bicycling, music headsets, and heart monitoring have all been plagued with intermittent blue tooth connection problems. So, at times, I find myself having to restart their app to keep the device connected, which is a minor annoyance.
I also use the QardioArm product to measure and monitor my blood pressure and am satisfied with it as well.
What follows is my anecdotal experiences of September 26, 2018 through the present day and I agreed to write about them here, in case it provides useful insight to others in some way.
As a person with a short-term history of heart problems, I tend to capture a lot of data with my devices. I monitor things like heart rate variability, blood pressure, Alivecor Kardia readings, sleep history, etc. I make an active attempt to monitor my levels of stress, but I know for certain that I lead a stressful life.I work longer hours than I should, probably sleep less than I should, exercise less than I like and should, and medicate and pray far less than I should.So, I don’t want to imply that anything that happened is the fault of the medical system, bad blue tooth connections, bad medical care, or bad advice from the Skeptical Cardiologist or any other medical professional. I tend to listen well, learn well, but I don’t always act as I should.But, I’m responsible for my choices, my decisions, and I live with the results of my actions.
With that said, I was sitting at the office on Wednesday September 26th, 2018 and was working away without a care in the world. As a computer programmer, I’m very sedentary and enjoy my work. I was wearing my QardioCore ECG strap at the time because I’m a big believer in capturing baseline data for my general living and lifestyle. I believe this data was invaluable in my first episode of heart problems, but have no supporting evidence to support my claim. At around 8:58:42 AM, I felt somewhat bad, and felt my heart racing. I glanced over at my phone which was showing the ECG trace at the time and noticed what I believed was Atrial Flutter at the time. But, after about 20 seconds, the ECG trace returned to normal, and I felt fine again. I made a quick note of the time, because I was busy, and continued working for the day.The Quardio App provides no diagnostic information, so it doesn’t analyze and interpret ECG patterns like the Alivecor Kardia app does. When I arrived at home later that day, I went back to look at the ECG trace, as the Quardio App easily allows that through features of the App. When I found the point in time of the ECG, I became concerned immediately because I believe that I was seeing a pattern that I recognized as Ventricular Tachycardia, a condition that comes in many forms, and has many causes, but can be fatal if not properly treated. As my cortisol levels increased, I contacted Dr. Google and just quickly verified that I wasn’t completely nuts, although I acknowledge there may be some partial nuttiness there. While going through this process, I experienced another 4 second episode which only increased my anxiety levels. After contacting my wife and asking her to return home, and informing some family members, I felt it best that I should contact the Skeptical Cardiologist after hours for input on my problem. I hate to bother the doctor, as he is a busy man, but contacted his after-hours number.While the operator on the other end of the line wondered what kind of nut case I was, she kindly contacted the doctor who promptly called me on my cell phone.I had informed the kind doctor that I had the device about three weeks prior, so he was already aware that I had the QardioCore. I quickly informed the doctor that I believed I had experienced at least one but possibly two cardiac events. After briefly talking, I hung up the phone and texted him photos of the screens from the Quardio App, so he could see the ECG tracings. Here are the photos that I sent to the Skeptical Cardiologist via text:
I believe this tool is valuable in many ways, but I believe that it was helpful for the Skeptical Cardiologist, as it helped narrow our focus of blood tests, scans, and potential procedures to run in a faster than normal basis. Normally, if I had not had evidence (accurate or not), I would have had to schedule an appointment, or go to ER. At that point, they would have either ordered an event monitor for me to wear while I was away from the hospital, or they would have had to admit me. Since I had a past history of Atrial Fibrillation, which isn’t quite as serious, we would have been sent home with an event monitor and instructions to take it easy and continue to take meds. We would have run more blood work, and more scans, but the point is that we would have been more broadly focused, as we would have had to generally guess as to the nature of the event and narrow it down.
I recognize that this is one of the controversies that is active in clinical cardiology, as I listen to podcasts by Dr. John Mandrola and others regarding the latest cardio devices, procedures and research. I realize that many Cardiologists are not in favor of devices like these, because they lead to uninformed conclusions, which leads to unneeded stress on both patients and their stressed-out doctors and cardiologists. I’ve listened to both sides of the argument, and I have my own opinions that I won’t express here. I will just say that I believe that this device saved me time, possibly my life (as I don’t know what I don’t know, unless I know to look), and some time in hastening and narrowing my therapy choices.
I will say that my wife and I were extremely happy with the services provided by his staff, himself, his colleagues, and the hospital staff as well. While I am confident I may be considered a difficult patient by some, or many, they were very thorough and kind in their treatment and explanation of my treatment options.
I hope that my experience adds helpful insight to the discussion. I’m confident that the Skeptical Cardiologist will add to this post, with his views on the events I’ve discussed above. And, I believe he appreciates having a Skeptical Patient every now and then as well.
As The Skeptical Patient wrote, this device is not sold in the United States. Having seen it in action now, I’m eager to get my hands on one and evaluate it further. It could dramatically alter home arrhythmia monitoring. For this patient it was incredibly helpful. If any of my European or Australian readers has experience with it please let me know.
Qardio makes a stylish, accurate and portable home BP monitor that I’ve written favorably about here.
N.B. Featured image of man running on beach with QardioCore is not of my patient.
The skeptical cardiologist picked up an Apple Watch 4 at the Galleria Apple Store in St. Louis today. The Apple employee who retrieved it told me that ECG recording capabilities were expected in the fall. Of course fall began today and it is not at all clear when, if ever, Apple will provide the software update to its AW4 that will provide ECG capabilities.
Fortunately, consumers already have the capability of recording a medical grade single lead ECG with any Apple Watch 2 or 3-using the KardiaBand from AliveCor.
Apple has hubristically proclaimed the AW4 as the ultimate guardian of our health and while setting it up I was asked if I wanted the watch to notify me if my heart rate dropped below 40 bpm for 10 minutes. Sure! Let’s see how irritating this feature will be.
After setting up the new watch I immediately attached my KardiaBand and installed the Kardia Apple Watch app.
I was able to open the Kardia app and it performed its normal SmartRhythm monitoring but when I tried to record an ECG, alas, nothing happened.
It appears that the KardiaBand does not work with the new Apple Watch 4. Yet.
I was informed by Ira Bahr at AliveCor that their “testing on AW4 is not yet complete. So at present, the device is not supported.”
Now I face a difficult decision-Do I wear my new AW4 with a non KardiaBand wrist band (and no ECG capability) or wear my old Apple Watch with the KardiaBand (and outstanding ECG capability.)
As I pointed out Friday, Apple’s claim that the ECG sensor on their new Apple Watch 4 (available “later this year”) is “the First ECG product offered over the counter directly to consumers” is totally bogus.
AliveCor’s Kardia mobile ECG device was approved by the FDA for over the counter direct to consumer sales on February 10, 2014. Apple had to have known this as they worked with AliveCor to bring the first Apple Watch based ECG device to FDA approval in 2017.
I tried but failed to get AliveCor founder Dr. David Albert’s thoughts on Apple’s disinformation but Yahoo finance was able to speak to Vic Gundotra, the CEO of AliveCor:
Over at the headquarters of AliveCor, a startup based in Google’s hometown of Mountain View, they, too, were surprised by the announcement, CEO Vic Gundotra said in a phone interview on Thursday. Gundotra is a former Googler, widely known as the executive behind the Google+ social network.
Gundotra was also surprised by Apple’s claims of ECG primacy
“We were watching [the announcement], and we were surprised,” Gundotra said. “It was amazing, it was like us being on stage, with the thing we’ve been doing for 7 years,” referring to AliveCor’s product for detecting atrial fibrillation (AFib), a tough-to-spot heart disorder that manifests as an irregular, often quick heart rate that can cause poor circulation.
“Although when they said they were first to go over-the-counter, we were surprised,” he continued. “Apple doesn’t like to admit they copy anyone, even in the smallest things. Their own version of alternative facts.”
One man’s alternative fact is another (less polite) man’s lie.
Gundotra apparently views Apple’s entry as a good thing
“We love that Apple is validating AFib; just wait until you see what AliveCor is going to do next,” he said. “We were a great restaurant in a remote section of town, and someone just opened a giant restaurant right next to us, bringing a lot more attention.”
And as I pointed out previously, the AliveCor mobile ECG device (not the Kardia Band) is significantly cheaper than an Apple Watch and has multiple studies showing its accuracy. Interestingly, Gundotra indicates AliveCor sales has increased after the Apple announcement,.
“Ours is $99, theirs is $399, our sales popped yesterday, big time,”
In March of 2017 AliveCor introduced Kardia Pro, a cloud-based software platform that allows physicians to monitor patients who use the Kardia mobile ECG device.
I have been utilizing the Kardia mobile ECG device since 2013 with many of my atrial fibrillation (AF) patients and have found it be very useful as a personal intermittent long term cardiac monitor. (see here and here)
I signed up for the Kardia Pro service about 3 months ago and all of my patients who purchased Kardia devices prior to March of 2017 have been migrated automatically to Kardia Pro by AliveCor.
Now (post March 2017), patients who acquire a Kardia device must sign up for the Kardia Pro service at $15 per month to connect with a physician.
I think this is money well spent and I’ll demonstrate how the service works with a few examples.
Monitoring Patients With Atrial Fibrillation
I saw a 68 year old man with persistent atrial fibrillation that was first diagnosed at the time of pneumonia in late 2017.
He underwent a cardioversion after recovering from the pneumonia but quickly reverted back to AF. His prior cardiologist offered him the option of repeat cardioversion and long term flecainide therapy for maintenance of normal sinus rhythm (NSR) but he declined.
When I saw him for the first time in the office a month ago I listened to his heart and to my surprise, noted a regular rhythm: an AliveCor recording in the office confirmed he was in NSR. The patient had been unaware of when he was in or out of rhythm
We discussed methods for monitoring his rhythm at this point which include a 24 Holter monitor, a 7 to 14 day Long Term Monitor, a Cardiac Event Monitor and a Mobile Cardiac Outpatient Telemetry device. These devices are helpful and although expensive are often covered by insurance. They require wearing electrodes or a patch continuously and the results are not immediately available.
I also offered him the option of monitoring his AF using a Kardia device with the recordings connected to me by Kardia Pro.
He purchased the device on his own for $99, downloaded the app for his smartphone and began making recordings.
I enrolled him in my Kardia Pro account and he received an email invitation with a code that he entered which connected his account with mine, allowing me to view all of his recordings as they were made.
When I log into my Kardia Pro account I can now view a graphic display of the recordings he has made with color coding of whether they were considered normal or abnormal by Kardia.
The patient overview page also displays BP information if the patient is utilizing certain Omron devices which work with Kardia.
The display shows that after our office visit he maintained NSR for 3 days (green dots) and then intermittently had ECG recordings classified as AF (yellow dots) or unclassified (black).
The more he used the device and got feedback on when he was in or out of rhythm the more he was able to recognize symptoms that were caused by AF.
I can click on any of the dots and six second strips of the full recording are displayed. In the example below I clicked on 2/27 which has both an unclassified recording (which is atrial flutter) and an AF recording
Clicking on the ECG strips brings up the full 30 second recording on a page that also allows me to assign my formal interpretation. In the example below I added atrial flutter as the diagnosis, changing it from Kardia’s unclassified (Kardia’s algorithm calls anything it cannot clearly identify as AF that is over 100 BPM as unclassified.)
The ECG can then be archived or exported for entry into an EHR.
The benefits of this patient being connected
to me are obvious: we now have an instantaneous patient-controlled method for knowing what his cardiac rhythm is doing whether he is having symptoms or not.
This knowledge allows me to make more informed treatment decisions.
The Kardia Pro Dashboard
When I log into kardia pro I see this screen.
It contains buttons for searching for a specific patient or adding a new patient. Adding new patients is a quick and simple process requiring input of patient demographics including email and birthdate.
From the opening screen you can click on your triage tab. I have elected to have all non normal patient recorded ECGS go into the triage tab.
Another patient’s Kardia Pro page shows that he records an ECG nearly every day and most of the time Kardia documents NSR in the 60s. Overall, he has made 773 recordings and 677 of them were NSR, 28 unanalyzed (due to brevity) , 13 unclassified and 55 showing AF.
Monitoring Rate Control In Patients With AF and Reversion Post-Cardioversion
Another patient I saw for the first time recently has had long-standing persistent AF. His previous cardiologist performed an electrical cardioversion a year ago but the patient reverted back to AF in 40 hours. Before seeing me he had purchased a Kardia mobile ECG device and was using it to monitor his heart rate.
After he accepted my email invitation to connect via Kardia Pro I was able to see his rhythm and rate daily. The Kardia Pro chart belowshows his daily heart rate while in atrial fibrillation. We utilized this to guide titration of his rate controlling medications. Such precise remote monitoring of heart rate in AF (which is often difficult to accurately assess by standard heart rate devices) obviates the need for office visits for 12 lead ECGs or periodic Holter monitors.
I performed a second cardioversion on him after which he made daily recordings documenting maintenance of NSR. With this system we can determine exactly when AF returns, information which will be very helpful in determining future treatment options.
Kardia Pro Plus Kardia Mobile ECG Creates Personal Intermittent Long Term Rhythm Monitor
There are many potential applications of the Kardia ECG device beyond AF monitoring (assessing palpitations, PVCs, tachycardia, etc.) but they are all enhanced when the device is combined with a good cardiologist connected to the device by Kardia Pro.
I’ve gotten spoiled by the information I get from my AF patients who are on Kardia Pro now. When they call the office with palpitations or a sense of being out of rhythm I can determine within a minute what their rhythm is wherever I am (excluding tropical beaches and mountain tops) or wherever the patient is (for the most part.)
On the other hand patients who are not on Kardia Pro have to come into the office for 12-lead ECGs. When they call I feel like my diagnostic tools are limited. Such patients usually end up getting one of the standard Long Term Monitoring (LTM) Devices. If I am fortunate, after a few days to weeks , the results of the LTM will be faxed to my office.
I am optimistic based on this early experience with Kardia Pro that ultimately this service in conjunction with the Kardia Mobile ECG device (or similar products) will replace many of the more expensive and inconvenient long term monitoring devices that cardiologists currently use.
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
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.
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.
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!
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.
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.
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:
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.
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.
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.
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.
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:
My Journal Grandfathered patients can bring their phones with them during an office visit and we can review all of their ECG tracings.
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.
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.
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.
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.
ACK recording was good quality but its algorithm could not classify the rhythm.
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 NSR
AliveCor/Kardia recordings on the same patient despite considerable and prolonged efforts to improve the recording were poor and were classified as “unreadable”
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.
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.
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.
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.
Sure enough, when I recorded his rhythm with ACK although NSR (with APCS) it was read as unclassified
AFA classified Lawrence’s rhythm as AF when it was in fact normal sinus with APCs.
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 AF
In one 90 year old man AFA could not make the diagnosis (yellow)
ACK correctly identified the rhythm as AF
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>
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.
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.