Category Archives: Medical/Fitness Devices

Heart Rate Recovery: A Simple and Powerful Predictor of Mortality Now Available On Your Apple Watch

Apple Watch and other fitness trackers have the capability to provide us with information on cardiovascular parameters which reflect the activity of the autonomic nervous system (ANS). Measures of the activity of the ANS reflect the balance between the sympathetic nervous system (which activates fight and flight responses) and the parasympathetic nervous system (which activates “rest and digest” activities) and have been shown to be powerful predictors of mortality.

Most of the attention in this areas has been on heart rate variability (HRV) with various wearables trying to promote HRV as a surrogate marker for stress. The OURA ring people for example state without evidence that “high heart rate variability is an indication of especially cardiovascular, but also overall health as well as general fitness.”

Although unimpressed with the HRV data from Apple Watch or the OURA ring I have recently discovered that I can get a more useful parameter of ANS tone from my Apple Watch-Heart Rate Recovery.

What Is Heart Rate Recovery?

Heart Rate Recovery (HRR) is the rate of decline in heart rate after the cessation of exercise. Basically you measure heart rate right when you stop exercising and again a minute later (and/or two minutes later) and subtract one from the other.

Unlike HRV you don’t really need any high tech devices to make this simple but highly reproducible measurement. You can simply measure your pulse the old-fashioned way by putting a finger on your carotid or radial artery and counting the beats.

What happens to the heart rate during exercise has long been considered to be due to the combination of parasympathetic withdrawal and sympathetic activation.

The fall in heart rate immediately after exercise has been shown to be a function of the reactivation of the parasympathetic nervous system. It is accelerated in athletes and blunted in patients with heart failure.

Heart Rate Recovery As A Predictor Of Mortality

A 1999 study published in the New England Journal of Medicine found that abnormally low HRR doubled the risk of dying over 6 years.

The study examined outcomes in 2428 consecutive adults (mean age 57 years, 63 percent men) without significant prior cardiac disease who were referred to the Cleveland clinic cardiac lab for nuclear stress testing.  Patients underwent symptom-limited exercise on a treadmill using a standard or modified Bruce protocol.

Heart rate was recorded at peak exercise and then patients walked upright and were walking at a speed of 1.5 miles per hour at a grade of 2.5 percent when heart rate was checked a minute later.

Median HRR was 17 beats per minute, with a range from the 25th to the 75th percentile of 12 to 23 beats per minute. Abnormally low HRR was selected as <13 beats/min and was found in 639 patients (26 percent).

In univariate analyses, a low value for the recovery of heart rate was strongly predictive of death, conferring a four-fold increased risk. After adjustment for multiple confounding factors including age and exercise capacity, patients with HRR <13 beats/min had a two-fold risk of dying.

This 20 year old study and HRR remain highly relevant. The paper has been cited 1001 times since publication and thus far in 2019 58 papers have referenced it.

In a follow up study this same Cleveland Clinic group looked at nearly 10 thousand patients undergoing treadmill ECG testing and found HRR <13 beats/min doubled the 5 year risk of death. In the figure below mortality jumps markedly as HRR drops below 13 and quite dramatically if <10 beats/min.

m_joc00680f2

 

 

 

 

 

Subsequent studies from different investigators confirmed that HRR is associated with mortality, independent of workload and myocardial perfusion defects, treadmill risk score, and even after adjusting for left ventricular function and angiographic severity of coronary disease.

There has been a lack of consistency in these studies in stress protocols, activity post-exercise and optimal duration of heart beat measurement post exercise.

This 2001 JACC paper determined that a 2 minute HRR <22 beats/min provided a better cut-point than one minue HRR <13 beats/min in predicting mortality at 7 years in male veterans. Individuals underwent maximal treadmill followed by lying down and those with an abnormal HRR were 2.6 times more likely to die. The HRR was equivalent to age and exercise capacity for predicting death.

Apple Watch and Heart Rate Recovery

It’s not entirely obvious how to view the heart rate recovery data on your Apple Watch but it is routinely logged if you record an activity and end it precisely at the end of the activity.  To see it you must leave the activity app and open the Heart Rate APP.

Scroll to the bottom of the screen and you will see HR data on your most recent activity including the peak HR and one minute recovery heart rate.

Click on that tab and the full and awe-inspiring graph of your recovery heart rate over 3 minutes is revealed. Here is mine which followed a 1.5 mile run at 6-7 MPH. I did not walk at 1.5 MPH on a 2.5% grade in recovery which would be needed if one wanted to more carefully compare a personal HRR to the numbers from the 1999 NEJM study.

My data shows a peak HR of 121 BPM which dropped to 90 BPM at one minute (121-90=31). Two minute recovery is 121-78 or 43 bpm. Both values are WNL

 

IMG_2A2C306430A7-1

The Watch only stores data on your last workout but if you go to the Activity app on your iPhone (something I had never previously done)  you will find under the workouts tab a complete listing of all previous workouts.

 

 

 

 

Click on the workout of interest and all the data from the workout is wondrously revealed including cadence, pace and  near the bottom heart rate changes. Swipe the heart rate changes during exercise to the left and the heart rate recovery graph is revealed. This time you will have to do the subtraction for yourself

Heart Rate Recovery-Simple, Powerful And Intuitive Measure of Autonomic Tone

So there you have it. Heart Rate Recovery (unlike HRV) is a simple parameter, easy to understand and measure. It yields information on your vagal/parasympathetic tone and has been proven to be a powerful and independent predictor of your overall mortality.

It makes more sense to pay attention to HRR if one wants a measure of your body’s autonomic tone than HRV.

If your one minute HRR is <13 beats per minute or two minute HRR <22 beats per minute this is a bad prognostic sign. If you have not been diagnosed with significant cardiovascular disease consider seeing a physician for evaluation..

For those who have been sedentary and are deconditioned or overweight, consider an abnormal HRR as a wake-up call to modify your lifestyle and improve your mortality.

For  healthy, asymptomatic individuals the HRR can serve as a marker for your overall cardiovascular fitness. Monitor it along with your exercise capacity, peak heart rate and resting heart rate to raise your awareness of how your exercise is influencing your overall autonomic nervous system balance.

Autonomously Yours,

-ACP

Atrial Fibrillation Detection, Personal ECG Monitoring and Ablation: A Patient’s Story

One of the joys of writing this blog is the communication it allows me with discerning  individuals and patients across the planet. One such reader, Mark Goldstein, discovered he was in atrial fibrillation after purchasing an Apple Watch 4.

He now utilizes both the Kardia Mobile ECG and the Apple Watch to aid in his personal monitoring of his atrial fibrillation and has been actively pursuing a rhythm control strategy under the care of his electrophysiologist.

I asked him to share with my readers his experience which recently culminated in an ablation.

What follows is his description with my editorial comments in green.


December 2018 I bought a crazy, expensive Apple Watch. That watch may have saved my life. I spend much of my days at a treaddesk (a combination desk and treadmill). I was curious to find out how much exercise I was doing. I bought the watch, put it on, and starting walking as I do almost every day. Two hours later the watch had an alarm. It was warning me about something called “atrial fibrillation,” It said, “your heart has shown signs of an irregular rhythm.” What! I never heard of afib before. I quickly learned about it. Heart palpitations, no. Pain/pressure in the chest, no. Sweaty, faint, dizzy, etc., no, no. no. I checked the box for tired but I assumed it was because of the amount of exercise I was doing.

The next day I was fortunate that I had a physical scheduled a year ago. I told my doctor that my “crazy, expensive watch” thinks I have afib. My doctor laughed, telling me about how he had checked and probed every part of my body for the last 20 years (the probing part I remembered well). As the exam was concluding, he was puzzled by the afib warning so he grabbed my wrist to check my pulse. A few seconds later he was asking the nurse to give me an EKG. Darn, the watch was correct (and for me it was correct 99% of the time when I had afib and when I was normal – praise to Apple).

Recording from Mark’s Apple Watch 4 showing atrial fibrillation with controlled ventricular response. Heart rate is only 82 beats per minute. The AW algorithm correction identifies atrial fibrillation.

(This is a great example of how atrial fibrillation can be missed by the routine office physical examination. Some patients, especially those with non-rapid heart rates (due to rate slowing meds like beta-blockers or to intrinsically  slow conduction of electrical impulses) are minimally symptomatic and their pulses don’t feel that irregular. Because the first symptom of afib can be stroke I am an advocate of screening)

Shortly I got to meet a cardiologist (like Dr. Pearson, they are all nice people). Another EKG, afib confirmed. As we were talking about my symptoms or lack of symptoms, he said that afib was a bit like Eskimo’s describing snow. Each snowflake is unique and each afib patient is unique. I was in persistent afib. Probably had been in this state for two or three years since my heart rate jumped while sleeping, exercising, and at rest.

(Each afib experience is unique but not all cardiologists are nice people. Mark has been fortunate.)

The treatment plan was a cardioversion, an electrical shock to the heart, or as my cardiologist described it “like rebooting a computer.”

(See my post on cardioversion here.)

As a tech person, I understood that. The risk of not fixing my afib was five times the likelihood of a stroke. The risks were minimal so I chose the cardioversion.

(A common misconception is that ablation or cardioversion eliminates or substantially lowers the risk of stroke in afib. This is not the case. I’ll devote a future post to delve into this issue.)

Cardioversion one lasted four days before my Apple Watch started to detect afib.

(I’ve described in detail how helpful patient utilization of personal ECG monitoring is in letting me know the rhythm status of patients prior to and following cardioversion here.)

The cardiologist next step was cardioversion two along with a drug to help with rhythm control. Number two lasted a month before I saw my heart rate jump again. I thought something was wrong even though my watch was not detecting afib. Another EKG, this time the result was aflutter. The cardioversions were indeed like a reboot of the computer. If you have a virus on your computer, a reboot may be a temporary fix but eventually the virus will return.

(There are many drugs whose purpose is to suppress the recurrence of atrial fibrillation. Mark was prescribed the extended release version of propafenone, a Type IC antiarrhythmic drug (AAD)  similar in efficacy and side effects to flecainide. Type IC AADs should only be used in patients with normal left ventricular function (which was demonstrated in Mark by an echo) and without significant coronary artery disease (typically proven by a negative stress test).

To Ablate Or Not To Ablate

Now I got to meet an electrocardiologist. He said my afib would return and recommended an ablation. He said it was unlikely to be a permanent cure but it would help.

The aflutter disappeared after a day or so. I thought my afib was gone too but should I have an ablation? Ablations are relatively safe but since I was afib free why have the procedure?

I purchased the new Kardia Mobile six-lead portable EKG, a miracle of technology. Highly recommended for peace of mind. Just like my watch, I was seeing normal sinus rhythm. So why get an ablation?

A cardiologist had a YouTube video talking about the decision to have an ablation or any medical procedure. How will it affect the quality of your life or the quantity (how long will you live). This was a simple analysis and I like simple. I heard from my cardiologist that the evidence is that an ablation will unlikely extend my life nor will it reduce my lifespan. It was likely to not affect my lifespan. I confirmed this via independent research (be an informed patient, your outcomes will be better). See Dr Pearson’s articles about the CABANA study and the scientific evidence on ablation).  So an ablation and quantity of life were neutral.

Importance Of Quality Of Life

Quality of life was more interesting. Could I do the things wanted to do with my life? Did afib affect my day-to-day life? Could I walk up a couple of flights of stairs without breathing hard? Was I getting tired at 10AM? Could I exercise? At the time, the answer was easy. I could do everything I wanted to do. The afib affect was just about zero except for blood thinner drugs which I suspect I will take forever. No ablation.

Then “the day.” I woke and checked my sleep app on my phone. Heart rate at night jumped. Hmm! I went to the gym. My heart rate while walking jumped too. I did 30 seconds of high-intensity exercise and my heart rate monitor said 205 beats per minute. My heart was beating so hard I had to sit for five minutes. I knew something was wrong. Then I climbed a couple of flights of stairs, something that would never bother me. I felt a shortness of breath. I knew my afib was back. I also knew that the quality of my life was now being affected. I could not do things I wanted to do. My watch and Kardia Mobile EKG confirmed what I knew.

I called my electrocardiologist and scheduled an ablation. He was right. Afib would return.

(Mark tells me that he was taken off his propafenone one month after the second cardioversion because “the PA said I no longer needed it since I was in sinus rhythm.” My practice would have been to continue the propafenone as long as well tolerated and effective in suppressing afib recurrence. In my experience, the recurrence of Mark’s afib may not have been a failure of medical therapy. I treat patients similar to Mark by continuing the anti-arrhythmic drug since the minimal risks are lowered by regular monitoring and I regularly see maintenance of SR.”)

(Other antiarrhythmic medications were mentioned to Mark but as they required a 3 day hospital stay he was not interested.)


Stay tuned: Part two Of Mark’s post will be about the ablation procedure which he recently underwent.

Skeptically Yours,

-ACP

Mark Goldstein works in the field of cybersecurity in the WashingtonDC area and can be contacted at https://www.linkedin.com/in/markhgoldstein/

Which Ambulatory ECG Monitor For Which Patient?

The skeptical cardiologist still feels that KardiaPro has  eliminated  use of long term monitoring devices for most of his afib patients

However not all my afib patients are willing and able to self-monitor their atrial fibrillation using the Alivecor Mobile ECG device. For the Kardia unwilling and  many patients who don’t have afib we are still utilizing lots of long term monitors.

The ambulatory ECG monitoring world is very confusing and ever-changing but I recently came across a nice review of the area in the Cleveland Clinic Journal of Medicine which can be read in its entirety for free here.

This Table summarizes the various options available. I particularly like that they included relative cost. .

The traditional ambulatory ECG device is the “Holter” monitor which is named after its inventor and is relatively inexpensive and worn for 24 to 48 hours.

The variety of available devices are depicted in this nice graphic:

For the last few years we have predominantly been using the two week “patch” type devices in most of our patients who warrant a long term monitor. The Zio is the prototype for this but we are also using the BioTelemetry patch increasingly.

The more expensive mobile cardiac outpatient telemetry (MCOT) devices like the one below from BioTel look a lot like the patches now. The major difference to the patient is that the monitor has to be taken out and recharged every 5 days. In addition, as BioTel techs are reviewing the signal from the device they can notify the patient if the ECG from the patch is inadequate and have them switch to an included lanyard/electrode set-up.

The advantage of the patch monitors is that they are ultraportable, relatively unobtrusive and they monitor continuously with full disclosure.

The patch is applied to the left chest and usually stays there for two weeks (and yes, patients do get to shower during that time) at which time it is mailed back to the company for analysis.

Continuously Monitoring,

-ACP

A Review Of SonoHealth’s EKGraph Portable ECG Monitor: Comparison To Apple Watch ECG And AliveCor’s Kardia ECG

The skeptical cardiologist keeps his eyes open for new, potentially improved ways of personal mobile ECG monitoring and when I saw the following comments on an afib forum I was intrigued:

I recently started using a SonoHealth product that I find MUCH MUCH superior to Kardia..

Really? MUCH MUCH superior? The more someone utilizes all caps
to emphasize theirs points the less I tend to believe them. But, as I am on a mission to discover the truth in all things cardiologic I went to the SonoHealth website and encountered this:

The EKGraph would indeed appear to be MUCH MUCH superior to Kardia mobile ECG if the website marketing can be believed.

Like the Kardia the EKGraph offers a personal ECG monitor obtained using the fingertips and syncing to an app on your smartphone.

The EKGraph claims to have 3 lead capability, something it emphasizes in its marketing but it is only capable of displaying one lead at a time and ,  similar to Kardia one can obtain lead II and precordial ECG leads by putting one electrode on the leg or chest.

Also similar to Kardia, the EKGraph promises “rhythm detection.” As we shall learn, however, rhythm detection by the EKGraph cannot be trusted whereas Kardia has a wealth of published data supporting its accuracy.

Unlike the Kardia, the EKGraph does have a “bright LCD screen” which displays the ECG wave pattern and heart rate along with the heart rhythm diagnosis.

I emailed SonoHealth and they were  kind enough to send me one of their ECG devices to demo. After spending some time with it I can say unequivocally that it should not be purchased or utilized by any patient who wants reliable personal mobile ECG monitoring with accurate diagnoses.

A few days later a package arrived containing the EKGraph in an Applesque box which also contiained a USB charging cable. In addition they included a carrying case and a tube of ECG gel.

 

 

Working With The SonoHealth APP

To make a recording one puts the metal strip on the left side of the device on hand, arm or leg and the other metal strip on the right side of the device on an opposing limb or the chest.

This very happy model gives you a feel for the size of the device and the method of making a Lead I recording.

 

 

 

 

 

 

 

 

It is possible to made a decent single lead ECG tracing with this device and view the tracing on the associated smartphone app. However, the recordings are typically very noisy and full of artifact making it hard to discern the rhythm. The software appears to lack appropriate filtering.

The SonoHealth app is free but getting it registered was a problem. On the company website support area several readers have complained of the same problem over the last few months:

 I am having trouble registering on the phone because when I hit the red button to register, I see the email and username fields at the top of the form, but when I click on email, the info fields jump to name, and I can’t scroll up to access those two fields. I then get a notification that those two fields are required to register. Any suggestions?

There is no response to this issue posted 3 months ago from the company.

Syncing with the app via Blutooth is straightforward. Pressing the sync button transfers all new tracings to the app where they can be reviewed.

Tracings can be emailed or printed.

Rhythm Detection

The major problem with the EKGraph  is that its  ability to diagnose  rhythm  is  very limited. This device has no published data verifying the accuracy of its rhythm diagnoses whereas the Apple Watch 4 and Kardia ECG devices do.  It it is not approved by the FDA.

I used the device on my self and despite identical rhythms the EKGraph called one “tachycardia” and the other “bradycardia.”

I tried using the SonoHealth on patients in my office who were in normal sinus rhythm and received wild, seemingly random diagnoses.

Whatever algorithm the device is using to diagnose rhythm is clearly not making allowances for poor quality recordings.

This patient is in NSR but the EKGraph calls it “tachycardia, VPB bigeminy” mistaking the artifact between the normal QRS beats and ventricular ectopic beats.

Multiple Sketchy Companies Utilizing Similar Hardware

I have noted other mobile ECG device with a remarkably similar appearance to the EKGraph.  A search on Amazon yields AliveCor’s devices and  the SonoHealth Ekgraph . The Amazon comparison page shows 3 additional  EKGraph identical-appearing devices seemingly from 3 different sketchy companies all priced at $79.

A consumer asked SonoHealth about the identical external appearance of SonoHealth’s and EMAY’s devices  and the company’s response was::

As a small new company making a new design for the outside shell didn’t seem viable. A mold from scratch costs anywhere from $65,000-$85,000. So our manufacturer allowed us to use their current mold to make the EKGraph.

So even though the outside is similar the software side is totally different. We have new and improved software. There’s also our own SonoHealth app that we developed from scratch.

SonoHealth is a USA company that provides excellent customer support.

I would disagree with SonoHealth’s assessment-there is nothing to suggest their software is either new or improved or even accurate.

The app that they developed from scratch is clunky and difficult to use.

Ratings and Online Presence of SonoHealth

SonoHealth posts on its website alleged reviews of EKGraph. They are uniformly positive. It’s hard to find anything that isn’t 5/5 stars. Apparently, all the problems I found with the product are unique to me.

However, these reviews should be taken with a grain of salt. A few weeks after acquiring my SonoHealth EKGraph I received an email from the company offering a gift card if I followed their precise instructions in writing a review:

TERMS: In order to receive the $10 giftcard reward you MUST write both a Company and a Product review. We will send each reviewer the egiftcard to the email that they provided when leaving the review. (For verification purposes, the email you enter when leaving the review must match the email associated with your order.)

This manipulation of the review process is shady and calls into question the validity of any review on the company website or Amazon.

Let The (Mobile ECG) Buyer Beware

The SonoHealth EKGraph is capable of making a reasonable quality single lead ECG. Presumably all the other devices utilizing the same hardware will work as well.

However, the utility of these devices for consumers and patients lies in the ability of the software algorithms to provide accurate diagnoses of the cardiac rhythm.

Apple Watch 4 and AliveCor’s Kardia mobile ECG do a very good job of sorting out atrial fibrillation from normal rhythm but the SonoHealth EKGraph does a horrible job and should not be relied on for this purpose.

The companies making and selling the EKGraph and similar devices have not done the due diligence Apple and AliveCor have done in making sure their mobile ECG devices are accurate.  As far as I can tell this is just an attempt to fool naive patients and consumers by a combination of marketing misinformation and manipulation.

I cannot recommend SonoHealth’s EKGraph or any of the other copycat mobile ECG devices. For a few dollars more consumers can have a proven, reliable mobile ECG device with a solid algorithm for rhythm diagnosis. The monthly subscription fee that AliveCor offers as an option allows permanent storage in the cloud along with the capability to connect via KardiaPro with a physician and is well worth the dollars spent.

Skeptically Yours,

-ACP

AliveCor’s KardiaBand Will No Longer Be Sold And Smart Rhythm Is No More

The skeptical cardiologist was quite enthusiastic about AliveCor’s Kardia Band for Apple Watch upon its release late in 2017.

I was able to easily make high fidelity, medical grade ECG recordings with it and its AI  algorithm was highly accurate at identifying atrial fibrillation  (see here). This accuracy was subsequently confirmed by research.

Many skepcard readers spent $200 dollars for the Kardia Band and had found it to be very helpful in the management of their atrial fibrillation.

However, in December of 2018 Apple added ECG recording to its Apple Watch 4, essentially building into the AW4  the features that Kardia Band had offered as an add on to earlier Apple Watch versions.

In my evaluation of the Apple Watch I found it to be “an amazingly easy, convenient and straightforward method for recording a single channel ECG” but its algorithm in comparison to AliveCor’s yielded more uncertain diagnoses.

Given it size, prominence and vast resources, Apple’s very publicized move into this area seemed likely to threaten the viability of AliveCor’s Kardia Band.

But then-interim CEO (and current COO)  Ira Bahr later told MobiHealthNews that his company’s broader business wasn’t threatened by its new direct competitor.

“We’re not convinced that Apple’s excellent, engaging product is a competitor yet,” he said in February. “We believe that from a price perspective, this product is least accessible to the people who need it most. If you’re not an Apple user, you’ve got to buy an Apple Watch, you’ve got to buy an iPhone to make the system work. So their technology is excellent, but we think the platform is both complicated and expensive and certainly not, from a marketing perspective, targeting the patient populations we target.”

Indeed, AliveCor’s Mobile ECG device and its recently released 6 lead ECG are doing very well but the threat to the viability of KardiaBand was real and MobiHealth News announced Aug. 19 that AliveCor had officially ended sales of the Kardia Band.

An AliveCor representative told MobiHealthNews that the company “plans to continue supporting KardiaBand indefinitely” for those who have already purchased the device. The company’s decision was first highlighted by former MobiHealthNews Editor Brian Dolan in an Exits and Outcomes report.

Mr. Bahr has confirmed to me that AliveCor does plan to continue supporting KardiaBand indefinitely. This includes replacement of KardiaBand parts.

Did Apple Kill Smart Rhythm?

The informed reader who notified me of AliveCor’s decision also notes:

The official reason is that they could not keep up with the Apple Watch updates and therefore the Smart Rhythm feature did not work properly.

I think many of us knew from the beginning that smart rhythm was not very accurate But in spite of that the Kardia band provided a valuable convenience over their other products.

It does appear that Smart Rhythm is no more.

AliveCor’s website was updated 6 days ago to state that Smart Rhythm was discontinued:

” due to changes beyond our control in the Apple Watch operating system, which caused SmartRhythm to perform below our quality standards”

Likely, as my reader was told, the frequent  AW4 updates plus the lack of a large KardiaBand user base made it unprofitable for AliveCor to continue to support Smart Rhythm.

Smart Rhythm, of course was AliveCor’s method for watch-based detection of atrial fibrillation. It clearly had limitations, including false positives but given AliveCor’s track record of dedication to high quality and accuracy I assumed it would improve over time..

Apple, on December 6, 2018  with the release of its watchOS 5.1.2 for AW4 announced its own version of Smart Rhythm at the same time it activated the ECG capability of AW4.

Apple called this feature “the irregular rhythm notification feature” and cited support for its accuracy from the widely ballyhooed Apple Heart Study (which I critiqued here.)

The irregular rhythm notification feature (TIRNF)was recently studied in the Apple Heart Study. With over 400,000 participants, the Apple Heart Study was the largest screening study on atrial fibrillation ever conducted, also making it one of the largest cardiovascular trials to date. A subset of the data from the Apple Heart Study was submitted to the FDA to support clearance of the irregular rhythm notification feature. In that sub-study, of the participants that received an irregular rhythm notification on their Apple Watch while simultaneously wearing an ECG patch, 80 percent showed AFib on the ECG patch and 98 percent showed AFib or other clinically relevant arrhythmias.

Despite widely publicized reports of lives being saved by TIRNF we still don’t know whether its benefits outweigh its harms. It is not clear what its sensitivity is for detecting atrial fibrillation and I have reported one patient who was in atrial fibrillation for 3 hours without her AW4 alerting her to its presence.

For AW4 users, absence of an alert should not provide reassurance that your rhythm is normal.

Thus is does appear that the Goliath Apple hath smote the David AliveCor in the watch-based afib battle. This does not bode well for consumers and patients as I think as competition in this area would make for better products and more accountability.

Philorhythmically Yours,

-ACP

N.B.

Per AliveCor the KardiaBand currently works with all all Apple Watches except the original one.

The Apple TIRNF per Apple:

is available for Apple Watch Series 1 and later and requires iPhone 5s or later on iOS 12.1.1 in the US, Puerto Rico, Guam and US Virgin Islands. The irregular rhythm notification feature does not detect a heart attack, blood clots, a stroke or other heart-related conditions including high blood pressure, congestive heart failure, high cholesterol or other forms of arrhythmia.

I Am A Keto-Friendly Cardiologist And I Love Keyto

The skeptical cardiologist has become more selective with regard to who he will accept as a new patient.  In practical terms this means I now call patients who want to see me and discuss with them why they want to see me, how they were referred or heard about me, and what their expectations are.

This might seem a little odd but turns out to be an excellent way for me to meet and smooth entrance for these newbies into my practice and gather important records and recordings prior to the first visit.

Recently, when I asked one of these potential patients why they had sought me as their cardiologist, the wife told me that through her internet research she had gleaned that I was a “Keto-friendly Cardiologist.”

Given that I have challenged conventional dogma on the dangers of dietary saturated fat and cholesterol and have written about ketosis (see here and here) a few times on this blog and defended Dr. Atkins I do actually consider myself “keto-friendly”.   However my prospective patient’s wife was not aware of the skeptical cardiologist as a blog writer.

How or why I was identified as Keto-friendly cardiologist was not clear.

I realized I needed to make it perfectly clear. It is now time to come out of the keto closet.

I am a “Keto-friendly cardiologist”!

I have dozens of patients who have been very successful using very low carb/high fat diets to help them lose weight and gain control of their diabetes and hypertension.

I don’t poo poo low carb high fat diets and I think they are vey compatible with a heart-healthy existence.

(I also advocate my version of a “plant-based diet“.)

In fact, lately I’ve gone back to dabbling with a Keto Diet myself.

To aid me in the dabbling I have found a device called Keyto to be the key to success and understanding of my ketosis.

Keyto: Breath Sensor for Ketosis and Weight Loss

When I went back to dabbling with ketosis in early 2019 I was using the Keto-Mojo finger prick device to measure my blood levels of beta hydroxybutyrate. I liked the precision this offered  compared to urine dip sticks but grew to dislike the need to prick my finger and create blood loss.

About a month ago I ordered I discovered the keto breath sensor KEYTO and have found since then that  it wonderfully simplifies  the process of being on a keto diet.

Keyto costs $99 and comes in a box the size of a video cassette  case.

In the box is the sensor device, four blowing mouthpieces, a very simple user manual, a AAA battery and a cute little bag for carrying the device

Ethan Weiss, MD, a highly respected preventative cardiologist and founder of Keyto includes a welcoming message for users which summarizes the mission of Keyto:

We designed the Keyto program to help you over-achieve your weight loss and health goals. With the Keyto Breath Sensor in this box, and the Keyto App on your phone, you have the key to unlocking success. You’ll be eating delicious foods, losing weight, and many  users even report an increase in energy and focus

Using Keyto Is Simple and Convenient

Getting started with Keyto is very easy: download the Keyto smartphone app, log in and follow the straightforward directions for pairing the breath sensor with the app.

Once paired via Bluetooth making measurements is easy. It’s important to understand the breathing technique needed and to facilitate this I strongly recommend watching the brief explanatory video Weiss has provided. Basically, you want to use a normal breath and blow for 10 seconds so that you are near the end of expiration when the device makes its recording.

To initiate a measurement you push the plus sign on the main “Journey” screen in the app then push the on button on the sensor.

Usually, if the sensor has been turned on and the app is activated the app immediately connects to the sensor, occasionally I have had to turn the sensor off and on again to initiated the connection.

At this point the sensor begins  warming up, reaching a temperature of 400 degrees Fahrenheit over a period of about 80 seconds.

The app displays the progress and offers you the option of answering some questions about how you are feeling and doing on the keto diet.

I often take my BP while this is going on. Sometimes I read the New Yorker. Frequently I listen to Radiohead (Climbing Up The Walls). It takes a while. Pay attention, though. You don’t want to miss your blowing window and have to repeat the process.

 

The app will give you a warning about 10 seconds prior to the time you need to blow. The graph to the right appears when it is time to blow and you can view the sensors output as it tracks the acetone it is seeing over the 10 seconds that you blow.

At the end of the blow you wait a few seconds, eagerly awaiting your score. Will you be in Ketosis?

 

Finally, your score is revealed. In this case I was congratulated for being in light ketosis with a fat burn of “medium high.” The highest score is an 8.

You can add notes to the record of your score

If you blow a 6 the app tells you that your fat burn is high and that you are in ketosis: “metabolizing fat like a champion.”

Accuracy of Keyto

When I first began using Keyto I checked the Keyto numbers versus the beta hydroxybutyrate (BOHB)  numbers I was simultaneously getting from my Keto-Mojo meter.

I found a Keyto 3 corresponded to 0.8 BOHB, a Keyto 4 to 0.9 BOHB, and a 5 to 1.0 BOHB.  That was enough to convince me that the device was accurate and useful in measuring my level of ketosis.

Given that it is so convenient compared to a finger stick I have stopped using the Keto-Mojo completely.

My observations confirm what Weiss and Ray Wu, MD, the cofounders of Keyto describe in very lucid prose here.

In extensive user testing, Keyto is directionally consistent with the more accurate commercially available blood meter. Keyto and blood β-hydroxybutyrate trend directionally the same in the majority of cases. Both go up and down in similar magnitude at different ranges of ketosis. There are some differences which are likely due to biology – the kinetics of clearance of acetone and β-hydroxybutyrate are not identical.

Some of the differences are also likely due to how we designed the Keyto program. Our primary goal was to develop a system that would give users the information they need to know i.e. if they are in ketosis, which would ultimately help promote healthy behavior change. Therefore, we chose not to report acetone concentrations in PPM or to attempt to convert PPM to blood β-hydroxybutyrate (mmol/L). The Keyto Level system was simply more effective, motivating, and fun without adding complexity and false precision.

I can make multiple measurements throughout the day without worrying about the cost or the discomfort of a finger stick. The ability to make multiple measurements means that I am getting very rapid and frequent feed back on how my dietary and lifestyle choices are effecting my level of ketosis.

Warning! Because the device is so convenient-literally you can have it with you at all times-you may find yourself blowing into it excessively. This may irritate your friends and loved ones, especially those that aren’t on a keto diet.

Keyto is Legitimate

The Keyto website has an excellent introduction to the keto diet (keto 101) and has numerous other very helpful resources for those who seek to lose weight using the diet.

In general I get a good feeling of integrity and legitimacy from every aspect of the Keyto operation.

I have a tremendous professional respect for Ethan Weiss, the cardiologist behind Keyto. He’s very active on Twitter and is typically spot on with his comments. He’s done a podcast with Peter Attia which serves as an excellent summary of atherosclerosis and coronary artery disease. He does really good basic science research involving growth hormone.

Weiss is now doing his own podcast called Best Known Method by Keyto which I highly recommend. It is not, surprisingly, focused on the keto diet or the keyto brand but interviews thought leaders in cardiology like Ron Krauss and Lisa Rosenbaum.

If you want to read more about how the Keyto breath sensor works see here. This is a very clear and concise description of the science behind the device and it is complete with references.

Ultimately, although I consider myself a keto-friendly cardiologist, I’m most interested in the diet that helps my patients achieve  and sustain their goals of weight loss and better health. For many this is the keto diet.

And for those who find the keto diet is optimal for their health I will be advising them to acquire a Keyto breath sensor and check out the programs Keyto offers to support their health goals.

Acetonely Yours,

-ACP

The Omron Evolv One-Piece Blood Pressure Monitor: Accurate, Quick And Connected

When it comes to self-monitoring of blood pressure the best device (assuming equivalent accuracy) is the one that patients are most likely to use.

The Omron Evolv has become that device for the skeptical cardiologist as it combines a unique one-piece design with built in read-out with a quicker, more comfortable  yet highly accurate BP measurement technique.

My previous favorite BP device, the QardioArm remains a close second.

Evolv Form and Function

The Evolv is sleek and stylish in appearance and has no external tubes, wires or connectors. It runs on 4 AAA batteries.

 

 

The  cuff is pre-formed and is incredibly easy to self-administer to the upper arm. Measurement is simple. Press the start button and it immediately starts inflating the cuff.

The results are displayed on an LCD screen on the cuff.

The Omron uses an oscillometric technique to measure the blood pressure as it is inflating. This “inflationary” technique has been shown to be as accurate as measuring during deflation but is much quicker. A study using the recently developed “Universal Standard Protocol” for evaluating the accuracy of BP devices showed that the Omron Evolv was highly accurate compared to gold standard sphygmomanometry.

Omron has come up with some slick marketing terms for the inflationary and pre-formed wrap aspects:

  • Intellisense Technology – Inflates the cuff to the ideal level for each use.
  • Intelli Wrap Cuff – For an easy and accurate reading

With the inflationary technique the cuff knows when to stop inflating, (hence “intellisense”) therefore, there is less tendency to go to higher pressures compared to the deflationary technique and less potential for discomfort from those higher pressures.

Evolv Communication-Sharing Results

The Evolv communicates via Bluetooth with the Omron Wellness (or Connect) smartphone app. Your BP  and heart rate measurements are easily transferred to this app and can be viewed over time.

My blood pressure and heart rate measurements over the last week.

If  one clicks on the little export icon at the upper right had corner of this summary screen you can “export CSV” which creates a file of BP measurements over a defined period that can then be emailed to yourself, your curious friends, or your doctor.

Another option is to export the summary report but this is a premium feature and requires payment.

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Monitoring Heart Rhythm and Blood Pressure-The Omron/Kardia Pro Connection

I’ve discussed in detail how management of my afib patients who have the Kardia mobile ECG device and connect to me via the internet using KardiaPro Remote has tremendously advanced their care.

AliveCor has partnered with Omron and the Omron Connect (or Wellness) app is essentially the Kardia app which my patients utilize to record their ECG recordings and share them with me.

With this app, therefore, patients who have the connection subscription service can utilize the Omron app to share both their ECG and BP recordings with me online. This is really quite an amazing development.

Below are recordings from one of my patients that I took from the patient screen which I view online.

The data can be viewed in various formats including this one which gives a good idea of daytime variation in BP as well as percentage recordings in goal range.

 

For me, this ability to rapidly view patient’s blood pressures over time in meaningful ways greatly facilitates management. If we could find a way to seamlessly import these data directly into our EMR it would an even bigger step forward.

Speaking To Your BP Cuff

I don’t use Alexa but Omron highlights how the Evolv works with Alexa:

 

 

Somehow, this doesn’t seem helpful to me but I tried asking Siri (with both my Apple Watch and iPhone) if she could give me info on my blood pressure and she failed miserably

 

 

 

 

 

 

 

Evolv-The Future of BP Management?

To summarize why I am so enthusiastic about this BP cuff

  • Portability and compactness. One piece design without tubes or wires.
  • Rigorously proven accuracy
  • Esthetically pleasing
  • Quicker and more comfortable than “deflationary” cuffs
  • Read-out on cuff-no separate unit or smartphone required
  • Communicates well with highly functional app for organizing or reporting BP measurements over time
  • Coordination of ECG measurements from Kardia and BP measurements on app through KardiaPro facilitates physician management of patient’s cardiovascular conditions.

Oscillometrically Yours,

-ACP

N.B. In the course of researching the Omron Evolv I looked at multiple home BP monitor review websites online. Almost without exception these were worthless.  I suspect many of these device review sites are funded by companies making the products. Others just aggregate information from company websites and regurgitate it without analysis. Websites with apparent consumer reviews are also suspect as I have found unscrupulous vendors are manipulating the whole review process.

Fortunately, your trusty skeptical cardiologist remains unsullied by any financial connections to corporate America. Or corporate Japan for that matter  (It appears Omron has its headquarters in Kyoto, Japan). However, Omron, if you are listening perhaps you can send me for my review one of your new Complete combined BP and EKG monitoring devices!

 

 

 

 

And one final detail. I checked just now and you can purchase the Evolv at Amazon for $69. Bundles that connect you to your doctor through the cloud and get you an Evolv plus or minus the Kardia ECG device at a reduced price are available through both the Kardia and Omron websites and apps.

 

Have You Used The SonoHealth EKGraph?

The skeptical cardiologist is evaluating a personal mobile ECG device made by SonoHealth called the EKGraph.

If any readers have encountered this device or have used it please email me your experience at drp@theskepticalcardiologist.com or leave a comment on the post.

Skeptically Yours,

-ACP

Why I Encourage Self-Monitoring Of Blood Pressure In My Patients With High Blood Pressure

The skeptical cardiologist primarily makes decisions on blood pressure treatment these days based on patient self-monitoring. If high readings are obtained in the office I instruct patients to use an automatic BP cuff at home and make a measurement when they first get up and again 12 hours later. After two weeks they report the values to me.

I described in detail the recommended technique in my 2018 post entitled “Optimal Home Blood Pressure Monitoring: Must The Legs Be Uncrossed and The Feet Flat?

Although I’ve been recommending self-monitoring to my patients for decades it is only recently that guidelines have endorsed the approach and good scientific studies verified its superiority. I was pleased when the 2017 ACC/AHA guidelines for High Blood Pressure made home self-monitoring of BP a IA recommendation.

And last year a very good study, the TASMNH4 was published which demonstrated the superiority of self-monitoring compared to usual care.

TASMINH4 was a parallel randomised controlled trial done in 142 general practices in the UK, and included hypertensive patients older than 35 years, with blood pressure higher than 140/90 mm Hg, who were willing to self-monitor their blood pressure. Patients were randomly assigned (1:1:1) to self-monitoring blood pressure (self-montoring group), to self-monitoring blood pressure with telemonitoring (telemonitoring group), or to usual care (clinic blood pressure; usual care group).

The home BP goal was 135/85 mm Hg, 5 mm Hg lower than the office BP goal. At one year both home self-monitoring groups had significantly lower systolic blood pressure than the usual care group.

This trial was not powered to detect cardiovascular outcomes, but the differences between the interventions and control in systolic blood pressure would be expected to result in around a 20% reduction in stroke risk and 10% reduction in coronary heart disease risk. Although not significantly different from each other at 12 months, blood pressure in the group using telemonitoring for medication titration became lower more quickly (at 6 months) than those self-monitoring alone, an effect which is likely to further reduce cardiovascular events and might improve longer term control.

Advantages of Home Self-Monitored Blood Pressure-Limitations of Office BPs

I described why I switched to home BPs in a post about the landmark  SPRINT trial in 2015:

Every patient I see in my office gets a BP check. This is typically done by one of the office assistants who is “rooming” the patient using the classic method with , listening with stethoscope for Korotkov sounds. If the BP seems unexpectedly high or low I will recheck it myself.

Often the BP we record is significantly higher than what the patient has been getting at home or at other physician offices.

There are multiple factors that could be raising the office BP: mental stress from driving to the doctor or being hurried or physical stress from walking from the parking lot.

In addition, I feel that multiple assessments of out of office BP over the course of the day and different days are more likely representative of the BP that we are consistently exposed to rather than one reading in the doctor’s office.

Accuracy and technique in the doctor’s office is also an issue.

Interestingly, we have assumed that manual office BP measurement is superior to automatic but this recent paper found the opposite:

Automated office blood pressure readings, only when recorded properly with the patient sitting alone in a quiet place, are more accurate than office BP readings in routine clinical practice and are similar to awake ambulatory BP readings, with mean AOBP being devoid of any white coat effect.

A patient left a comment to that paper which is quite insightful:

I had a high blood pressure event several years ago. Since then I have monitored my BP at home, sitting with both feet flat on the floor, not eating or drinking, not speaking or moving around, on a chair with a back, and without clothes on the arm being used for the measure. My BP remains normal.

I have never had my BP taken correctly in a doctor’s office. They will do it while I am speaking with the doctor, sitting on an exam table with my legs swinging, with the monitor band over my heavy winter sweater, right after I have sat down. They do not ensure that my arm is supported or at the right height. If I recommend that I take off my sweater, or move to a chair with a back, they tell me that is not needed. I have decided to refuse such measurements. How can they possibly be monitoring my health this way?

This patient’s observations are not unique and I suspect the majority of office BPs have most if not all of the limitations she describes.

Self Monitoring Improves Patient Engagement In BP Control

I have found self-monitoring of patient’s BP to substantially enhance patient engagement in the process. Self-monitoring patients are more empowered to understand the lifestyle factors which influence their BP and make positive changes.

Blood pressures are amazingly dynamic and as patient’s gain understanding of what influences their BP they are going to be able to take control of it.

I take my BP almost daily and adjust my BP medications based on the readings. After prolonged work or exercise in heat, for example, BPs will decline to a point where I’m light headed or fatigued. Less BP med at this time is indicated. Conversely, if I’ve been overly stressed BPs increase and upward titration of medication is warranted.

With some of my most engaged and enlightened patients we perform similar titrations depending on their circumstances. Sometimes patients perform these titrations on their own and tell me about them at the next office visit.

What’s The Best Way To Communicate Home BPs?

Many of my patients provide me with a hand-written record of their BPs over two weeks.  Some mail them to me, others bring them in to the office. We scan these into the EMR. I look at these and make an estimate of the average systolic blood pressure, the variation over time and the variation during the day. It’s not feasible for me or my staff to enter the numbers or precisely obtain an average.

Some patients send us the numbers through the internet-based patient portal into the EMR. This is preferable as I can view these and respond quickly and directly back to the patient with recommendations.

More and more patients are utilizing their smart phones to record and aggregate their health data and will bring them in for me to look at during an office visit. I’ve described one stylish and slick BP cuff, the QardioArm which has neither tubes nor wires and works through a smartphone app. Omron , also has multiple cuffs which communicate via BlueTooth to store data in a smartphone app.

Ideally, we would have a way for me to view those digitally recorded BPs with nicely calculated averages online and within the EMR. Unfortunately, such connectivity is not routinely available.

However, for my patients who are already monitoring their heart rhythms with a Kardia mobile ECG and are connected with me online through KardiaPro Remote I can view their BP recordings online.

I’ll discuss in detail in a subsequent post the Omron Evolv home automatic BP cuff (my current favorite) which is wireless and tubeless and connects seamlessly to KardiaPro allowing me to view both BP and heart rhythm (and weight) recordings in my patients

To me, this empowerment of patients to record, monitor and respond to their own physiologic parameters is the future of medicine.

Sphygmomanometrically Yours,

-ACP

From the 2017 ACC/AHA BP guidelines

and the proper technique for office BP measurement

 

 

An Early Look At AliveCor’s Amazing KardiaMobile 6L: Accurate 6 Lead ECG On Your Smartphone

The skeptical cardiologist has been evaluating a demo version of AliveCor’s new KardiaMobile 6L.

I have been a huge advocate of Kardia’s single lead ECG and use it with great success in dozens of my afib patients. I’ve written about how this personal ECG monitoring empowers patients and providers and is a crucial component of the enlightened medical management of afib.

In less than a month AliveCor plans to release its KardiaMobile 6L which will provide 6 ECG leads  using a smartphone based mobile ECG system that is similar to the Kardia single lead system.

AliveCor’s website proclaims “This is your heart x 6.”

 

 

 

I was fortunate enough to obtain a demo version of the 6L and have been evaluating it.

My  first impressions are that this is a remarkable step forward in the technology of personal ECG monitoring. I’m not sure if I would call it “your heart x 6” but I feel the ability to view six high quality leads compared to one is definitely going to add to the diagnostic capabilities of the Kardia device.

Kardia 6L Setup And Hardware

The 6L is similar in design and function to the single lead device.

I’m including this cool spinning video (from the AliveCor website) which makes it appear, slick, stylish and  futuristic

Once paired to the Kardia smartphone app (available for iOS or Android smartphones for free) it communicates with the smartphone  using BLE to create ECG tracings.

Like the single lead Kardia the 6L has two sensors on top for left and right hand contact. But in addition, there is a third on the bottom which can be put on a left knee or ankle.

The combination of these sensors and contact points yield the 6 classic frontal leads of a full 12 lead ECG: leads I, II, III, aVL, aVR, and aVF. This is accomplished, AliveCor points out “without messy gels and wires.

I found that using the device was simple and strait-forward and we  were able to get high quality tracings with minimal difficulty within a minute of starting the process in all the patients we tried it on.

The  Diagnostic Power Of Six Leads

Below is a tracing on a patient with known atrial fibrillation. The  algorithm correctly diagnoses it. With 6 different views of the electrical activity of the atrium I (and the Kardia algorithm)  have a better chance of determining if p waves are present, thereby presumably  increasing the accuracy of rhythm determination

Depending on the electrical vector of the left and right atria, the best lead to visualize p waves varies from patient to patient, thus having 6 to choose from should improve our ability to differentiate sinus rhythm from afib.

In the example below, the Kardia 6L very accurately registered the left axis deviation and left anterior fascicular block that we also noted on this patient’s 12 lead ECG. This 6L capability, determining the axis of the heart in the frontal plane,  will further add to the useful information Kardia provides.

 

For a good summary of axis determination and what abnormal axes tells us see here.

The History of ECG Leads

When I began my cardiology training the 12-lead ECG was  standard but it has not always been that way. I took this timeline figure from a nice review of the history of the ECG

 

 

Einthoven’s first 3 lead EKG  in 1901 was enormous.

Old string galvanometer electrocardiograph showing the big machine with the patient rinsing his extremities in the cylindrical electrodes filled with electrolyte solution.
 It is mind-boggling to consider that we can now record  6 ECG leads with a smartphone and a device the size of a stick of gum

For the first 30 years of the ECG era cardiologists only had 3 ECG leads to provide information on cardiac pathology.  Here’s a figure from a state of the art paper in 1924 on “coronary thrombosis” (which we now term a myocardial infarction) showing changes diagnostic of an “attack” and subsequent atrial fibrillation

In the 1930s  the 6 precordial leads were developed providing more information on electrical activity in the horizontal axis of the heart. The development of the augmented leads (aVr, aVL, aVF) in 1942  filled in the gaps of the frontal plane and the combination of all of these 12 leads was sanctified by the AHA in 1954.


I’ll write a more detailed analysis of the Kardia 6L after spending more time using it in patient care.

Specifically I’ll be analyzing (and looking for published data relative to):

-the relative accuracy of the 6L versus the single lead Kardia for afib determination (which, at this point would be the major reason for current Kardia users to upgrade.)

-the utility of the 6L for determination of cardiac axis and electrical intervals in comparison to the standard 12 lead ECG,  especially in patients on anti-arrhythmic drugs

For now, this latest output from the meticulous and thoughtful folks at AliveCor has knocked my socks off!

Stockingfreely Yours,

-ACP

N.B. If one uses the single lead kardia device in the traditional manner (left hand and right hand on the sensors) one is recording ECG lead I. However, if you put your right hand on the right sensor and touch the left sensor to your left leg you are now recording ECG lead II and if to the right leg, ECG lead III.

I describe this in detail here. For certain individuals the lead II recordings are much better than lead I and reduce the prevalence of “unclassified” recordings.

My feeling is that by automatically including the leg (and leads II and III) the 6L will intrinsically provide high voltage leads for review and analysis, thereby improving the ability to accurately classify rhythm.

And (totally unrelated to the 6L discussion) one can also record precordial ECG leads by putting the device on the chest thus theoretically completing the full 12 leads of the standard ECG.


Please also note that I have no financial or consulting ties to AliveCor.  I’m just a big fan of their products.