Tag Archives: atrial fibrillation

The New Apple Watch 4: Cardiac Accuracy Unknown, “Game-Changing” Benefits Overblown

On February 10, 2014 AliveCor, Inc. announced that its heavily validated personal  mobile ECG monitor had received FDA over-the counter clearance. Previously the device, which allows recording of a single-lead ECG and, in conjunction with a free smart-phone app, can diagnose atrial fibrillation was only available by prescription.

Since 2013, I have been successfully using this device with my patients who have atrial fibrillation (and writing about it extensively)

Apple COO Jeff Williams standing in front of (presumably) an ECG obtained by Apple Watch 4. It’s OK quality (but smallish p waves). Is that the best they could do? Notice that it is making a diagnosis of sinus rhythm. This PDF can be mailed “to your doctor.”

I was shocked, therefore, to hear the COO of Apple, Jeff Williams, announce that Apple will be offering in its new Apple Watch 4  “the first ECG product offered over the counter directly to consumers.”

This seemed blatantly inaccurate as AliveCor’s device clearly preceded by 4 years Apple’s claim.

Furthermore, AliveCor’s Kardia Band which converts any Apple Watch into a single-lead ECG  (which I’ve written about here and here) has been available and providing the Apple Watch-based ECGs since November 30, 2017.

AliveCor has an outstanding website which documents in detail all the research studies done on their products (there are dozens and dozens of linked papers) and all of their press releases dating back to 2012. It also explains in detail how the product works.

The title of their November 30, 2017 release was  FDA Clears First Medical Device Accessory for Apple Watch®

AliveCor shortly thereafter (December 12, 2017) announced Smart Rhythm , an Apple Watch app that monitors your rhythm and alerts you if it thinks you are in atrial fibrillation. I’ve discussed Smart Rhythm here.

Apple’s Watch will tell you that you are not in atrial fibrillation. Given that we don’t know how accurate it is, should that be reassuring?

The new Apple Watch’s rhythm monitoring app sounds a lot like Smart Rhythm but without any of the documentation AliveCor has provided.

So, within 10 months of Alivecor providing the world with the first ever wearable ECG (and proven its accuracy in afib) Apple seems to have come out with a remarkably similar product.

The major difference between Apple and AliveCor is the total lack of any reviewable data on the accuracy of the Apple device. Yes, that’s right Apple has provided no studies and no data and we have no idea how accurate its ECG device is (or its monitoring algorithm).

For all we know, it could diagnose sinus rhythm with frequent APCS or PVCs consistently as atrial fibrillation, sending thousands of Watch 4 wearers into a panic and overloading the health care system with meaningless alerts.

Apple’s website claims

Apple Watch Series 4 is capable of generating an ECG similar to a single-lead electrocardiogram. It’s a momentous achievement for a wearable device that can provide critical real-time data for doctors and peace of mind for you.

Apple’s “momentous achievement” was actually achieved 10 months earlier by AliveCor and if its monitoring algorithm and ECG system are significantly worse than the proven AliveCor system they will be destroying the peace of mind of users.

Electrodes built into the Digital Crown and the sapphire back crystal allow sensing of cardiac electrical signals. Did Apple get this idea from AliveCor?

After describing the Apple Watch’s new health features, Jeff Williams introduced Ivor Benjamin, MD, the President of the American Heart Association. Benjamin proceeded to describe the new Apple Watch cardiac features as “game-changing”, noting that the AHA is committed to helping patients be “proactive.”

Does  Benjamin have access to the accuracy of the Apple Watch ECG sensor? If so, he and the AHA should immediately share it with the scientific community. If not, by endorsing this feature of the Watch he should be ashamed. Users need to know if he or the AHA was paid any money for this appearance. Also, we should demand to know if (as the prominent AHA logo suggested and news reports implied) the AHA is somehow endorsing the Apple Watch.

Frequent readers know I’m a huge Apple fan but this Apple Watch business makes me think something is rotten in the state of Apple.

Skeptically Yours,

-ACP

Update On The Kardia Band Apple Watch Accessory: Accuracy In Atrial Fibrillation Pre and Post Cardioversion

As I described here, the Kardia Band (KB) is an FDA-approved Apple Watch accessory available to the general public without a prescription which records a high quality single-lead ECG.

I’ve been using mine now for a while and can confirm the ease and accuracy of the ECG recordings it makes. I find recordings made with my Apple Watch/Kardia Band are reliably high quality with minimal artifact (unless I’m running on a treadmill.)

Once the 30 second recording is completed, the Kardia app on the Apple Watch takes about 5 seconds to process the information using an AI algorithm and then makes a determination of normal sinus rhythm (NSR), atrial fibrillation or unclassified.

 

 

The New Study

A study published in the June JACC examined the accuracy of  Alivecor’s Kardia Band in detecting atrial fibrillation (AF.)

In the JACC study, investigators from the Cleveland Clinic studied  100 consecutive patients presenting for cardioversion from AF with recordings made before  and after the procedure. KB interpretations were compared to 12 lead ECGS read by electrophysiologists.

KB interpretations  identified AF with  93% sensitivity and 84% specificity. Of the total 169 recordings, 34% were unclassified due to short recordings, low-amplitude p waves, and baseline artifacts.

The authors concluded that the KB algorithm for AF detection, when it is supported by a physician review can reliably differentiate AF from NSR.

(Of note the lead author on this study is on the advisory board of Alivecor the maker of the KB and AliveCor (AliveCor, Mountain View, CA) provided the Kardia Band monitors which were connected to an Apple Watch and paired via Bluetooth to a smartphone device for utilization in the study. AliveCor was not involved in the design, implementation, data analysis, or manuscript preparation of the study.)

My Updated Kardia Experience

I have found the standard Kardia device to be immensely helpful in the management of my afib patients before and after cardioversions (see my prior description here). The paper mentions that 8% of these pre-cardioversion patients showed up for the procedure in normal sinus rhythm, noting that

For each of these patients, the automated KB algorithm did not erroneously identify AF, and the physician interpretation of the KB recording correctly confirmed SR in each case.

Needless to say, it is better to find out a cardioversion is not needed before the patient shows up for the procedure. I would estimate this happens about 5-10% of the time in my practice.

The Kardia device or the KB is also really helpful post cardioversion. If the patient makes daily recordings (which I can review on Kardia Pro online) h/she and I know exactly how long sinus rhythm persisted before reverting back to AF.

This is important information which impacts future management decisions.

Kardia Band Versus Standard Kardia Device

None of my patients have purchased the Kardia Band most likely due to the cost and the fact that they don’t have an Apple Watch. If you have an Apple Watch and want to monitor your heart rhythm I think the KB is a good choice. Otherwise, the original AliveCor mobile ECG device continues to do a fantastic job (in conjunction with Kardia Pro, see here).

The combination of Kardia and Kardia Pro has substantially reduced my use of expensive and annoying long term monitors in my AF population.

In my next update on the KB I will share a reader’s real world description of the pros and cons of the KB (with Smart Rhythm monitoring) in a patient post cardioversion for AF.

Skeptically Yours

-ACP

Is It Safe To Consume Grapefruit If You Take The Blood Thinner Apixiban (Eliquis)?

A patient of mine with atrial fibrillation taking the blood thinner eliquis told me that she had eaten grapefruit for two days in a row and then developed a nose bleed. She had heard of the interaction between grapefruit and certain medications and wondered if this had caused her nose bleed.

I was unaware of any eliquis/grapefruit interaction but thought this was a remarkably astute observation and question and set about to research it properly.

Among other things, I discovered that some researchers believe the grapefruit-drug interaction to be a widespread , underreported and  highly significant problem while others feel it is overblown and a rare cause of clinically important side effects.

For those, who prefer not to delves into the gory details I give you the crux of what BMS/Pfizer, the makers of apixiban (Eliquis) told me and with which I agree:

When consumed in usual dietary volumes, grapefruit juice is considered a moderate inhibitor of CYP3A4. Therefore a dose adjustment of apixaban is not expected to be required.

In other words, although not formally studied, there is no evidence that apixiban levels are increased by moderate grapefruit juice ingestion to a degree that would cause significant bleeding complications.

Although multiple sites on the internet (including the unreliable Web MD) will tell you of a potentially dangerous interaction between grapefruit and apixiban this theoretical interaction has not proven clinically significant.

Interactively Yours,

-ACP

Below is the full text of the letter BMS sent me

Bristol-Myers Squibb and/or Pfizer have not conducted any studies evaluating the concomitant use of apixaban and grapefruit juice. The decision to prescribe apixaban in patients who are concomitantly taking grapefruit juice is a clinical decision for the treating physician based on the individual’s circumstances and inaccordance with the full prescribing information for apixaban.

While in vitro data indicates grapefruit juice can inhibit both cytochrome P450 (CYP) 3A4 and P-glycoprotein (P-gp), clinical evidence suggests that grapefruit juice mediated interactions would be primarily due to the inhibition of CYP3A4 and the contribution of P-gp inhibition may be limited.1, 2 When consumed in usual dietary volumes, grapefruit juice is considered a moderate inhibitor of CYP3A4.1 Therefore a dose adjustment of apixaban is not expected to be required.

Apixaban is eliminated from the body through multiple pathways, with approximately 25% of the administered dose recovered as metabolites. The main metabolic pathway for apixaban is through CYP3A4/5, with minor contributions from other CYP isoenzymes. Apixaban is also a substrate of transport proteins P-gp and breast cancer resistance protein.3

  1. [1]  Hanley MJ, Cancalon P, Widmer WW,et al. The effect of grapefruit juice on drug disposition. Expert Opin Drug Metab Toxicol. 2011; 7(3):267-286.
  2. [2]  Farkas DG and Greenblatt DJ. Influence of fruit juices on drug disposition: discrepancies between in vitro and clinical studies. Expert Opin Drug Metab Toxicol. 2008;4(4):381-393.
  3. [3]  Eliquis® (apixaban) Package Insert. Bristol-Myers Squibb Company, Princeton, NJ and Pfizer Inc, New York, NY

AliveCor Mobile ECG : Ways To Minimize Low Voltage and Unclassified Recordings

Sometimes AliveCor’s Mobile ECG device yields unclassified interpretations of recordings. Understandably if you want to know whether your rhythm is normal or atrial fibrillation, the unclassified  classification can be very frustrating.

There are various caues of an unclassified tracing with different solutions.  Some unclassified recordings are due to a heart rate over 100 BPM or under 50 BPM and cannot be fixed. Similarly, some patients with ectopic beats like PVCS may consistently generate unclassified interpretations (see my discussion here).

Artifacts induced by poor recording techniques are common as a cause and almost always can be fixed.

These can be reduced by minimizing motion, extraneous noise, and maximizing contact with the electrodes.  Follow all the steps AliveCor lists here.

For me, the following step is crucial

  • If your fingers are dry, try moistening them with antibacterial wipes or a bit of lotion

And be aware the device needs to be near the microphone of your iPad or smartphone.

Low Voltage As Cause of Unclassified Kardia Recordings

Another cause of unclassified interpretations is a low voltage recording (which I initially discussed here.).

At the recent ACC meeting I asked Alivecor inventor and CEO David  Albert if he had any solutions to offer for those who obtain unclassified low voltage AliveCor tracings.

He told me that the cause is often a vertically oriented heart and that recording using the lead II technique can often solve the problem.

Lead II involves putting one electrode on your left knee and one your right fingers as described in this video:

Reader “J”  recently sent me a series of Kardia ECG recordings,  some of which were unclassified , some normal and one read as possible atrial fibrillation.

The unclassified and possible AF tracings looked like this:

 

They were very regular with a rate between 80 and 100 BPM but they totally lacked p waves. It was not clear to me what the rhythm was on these tracings.

Other tracings had lowish voltage but the p waves were  clearly visible  and Kardia easily classified them as normal

Lowish voltage with p waves (Type B)

 

Good QRS voltage with clear p waves ( Type B

 

Still others had improved QRS voltage with clear p waves and were also classified  appropriately as normal

 

After some back and forth emails we discovered that the ECG recordings with no p waves were always  made using the chest lead recording.   AliveCor-describes this as follows:

  • For an Anterior Precordial Lead, the device can be placed on the lower left side of the chest, just below the pectoral muscle. The bottom of the smartphone or tablet should be pointing towards the center of the body.

Mystery solved!

There is an abnormal cardiac rhythm that is regular between 80 and 100 BPM with no p waves and normal QRS called junctional tachycardia but in J’s case the absent p waves are related to the recording site.

Also, note that for this young woman the lead II voltage (Type B tracing) is much higher than the standard, lead I voltage (type A tracing).

Lead II With Pants On

After Dr. Albert told me of the advantages of Lead II I responded that it seemed somewhat awkward to take one’s pants off in order to make an ECG recording.

He immediately reached in his suit pocket and pulled out a pen-shaped device and began spraying a liquid on his left knee.

To my surprise he was able to make a perfect Lead II recording without taking his pants off!

Lessons learned from reader J and Dr. A:

  • Consider trying different leads if the standard Lead I (left hand, right hand) is consistently yielding unclassified ECG recordings
  • Try Lead II (left knee, right hand) to improve voltage and recording quality
  • You can record off your knee even with your pants on if you are prepared to spray liquids on your pants

Pantsonically Yours,

-ACP

Can AliveCor’s Mobile ECG Device Combined With Its Kardia Pro Cloud-Based Platform Replace Standard Long Term Rhythm Monitors?

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.

kardia pro wc monthly

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.

dashboard karia pro 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.

Other Examples

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.

Skeptically Yours,

-ACP

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

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

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

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

What is SmartRhythm?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

How Does SmartRhythm Perform During Exercise?

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

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

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

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

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

Afib Patient Experience

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

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

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

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

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

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

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

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

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

Fastidiously Yours,

-ACP

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

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

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

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

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

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

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

Review of Kardia Band Mobile ECG for Apple Watch

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

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

What’s In The Box

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

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

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

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

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

Set UP

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

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

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

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

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

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

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

I sent out pleas for assistance to AliveCor.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Proarrhythmically Yours

-ACP

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

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

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

Blood Thinners (Oral Anticoagulants) For Atrial Fibrillation: Who Should Take Them and Which One To Take

The most serious  adverse consequence of having atrial fibrillation is stroke. Since we have safe and effective ways of preventing afib-related stroke with oral anticoagulant drugs (blood thinners), a major decision for the newly diagnosed patient with atrial fibrillation is “should I take a blood thinner?”

To answer this question the afibber should engage in a lengthy discussion with his/her health-care provider which results in a shared and informed  decision. Such discussion must cover your risk of stroke, the benefits of blood thinners in preventing stroke, the bleeding risks of blood thinners and the pros and cons of the five oral anticoagulants available to prevent stroke.

Estimating Your Risk of Stroke With Afib

The best way we have of estimating a patient’s risk of stroke if they have atrial fibrillation (AF) is by the CHA2DS2-VASc scale (which I like to call the Lip scale)

Stroke Risk EstimationThis scale take the factors we know that increase the risk of stroke and assigns 1 or 2 points. The acronym comes from the first letter of the factors that are known to increase risk as listed to the left.

Most of the factors get 1 point, but prior stroke (S) and age>75 (A) get 2 points.

We then add up your points and use another chart (or app) to calculate the risk of stroke per year.

CHA2 stroke riskYour risk of stroke is very low if you have zero risk factors; it gets progressively higher as you reach the maximum number of 9.

Treatment with an oral anticoagulant (OAC),  either warfarin, or one of the four novel anticoagulant agents (NOACS), is recommended when score is >/=2 corresponding to a  risk of stroke  above 1-2% per year.

These blood thinners have consistently been shown to lower your risk of stroke or systemic embolization (when a clot from the heart goes somewhere other than the brain) by almost 70%.

The higher the risk, the more the benefit of these blood thinners in preventing stroke.

Both European and American guidelines recommend using the CHA2DS2-VASc score for initial risk stratification. The European  guideline recommends OAC therapy for males with a CHA2DS2-VASc score ≥1 and for female patients with a score ≥2., whereas the American guideline recommends use of OAC if the CHA2DS2-VASc  score is ≥2 for men and women.

I’ve been using the CHA2DS2-VASc scale for several years in my afib patients. I try to review the patient’s risk of stroke and their risk of bleeding during every office visit, and decide whether they should be on or off an OAC.

Bleeding From Blood Thinners

All OACs cause increase bleeding. They don’t discriminate between bad clots that cause strokes and good clots that stop you from bleeding.

If you’re taking one you are more likely to have nose bleeds, bleeding into the intesitnal tract or urine and you will bleed longer when cut and more profusely if in an accident. In lower stroke risk patients, the bleeding risk of OAC of 1% per year may outweigh the benefits conferred by stroke reduction.

I wrote a post entitled “Why Does The TV Tell me Xarelto Is a Bad Drug” which points out that law suits against the makers of the newer OACs are frivolous and that these NOACs are likely more safe and effective than warfarin.

In recent years, four new drugs for reducing strokes in patients with atrial fibrillation which are much less influenced by diet and medications have gained approval from the FDA. These are generally referred to as “novel anticoagulants” reflecting their newness, different effects from warfarin or aspirin, and their blood thinning properties.  The first  (brand name Pradaxa) was released to much excitement and fanfare in October, 2010.  The press release for this approval read as follows:

PRADAXA, an oral direct thrombin inhibitor2 that was discovered and developed by Boehringer Ingelheim, is the first new oral anticoagulant approved in the U.S. in more than 50 years. As demonstrated in the RE-LY® trial, PRADAXA 150mg taken twice daily has been shown to significantly reduce stroke and systemic embolism by 35 percent beyond the reduction achieved with warfarin, the current standard of care for patients with non-valvular atrial fibrillation. PRADAXA 150mg taken twice daily significantly reduced both ischemic and hemorrhagic strokes compared to warfarin

What was very clear from the study with Pradaxa  and stated very clearly in all publications and patient and doctor  information sources was that just like warfarin, patients could have severe bleeding complications, sometimes fatal. Overall serious bleeding complications were about the same (the rate of major bleeding in patients Pradaxa  in the RE-LY trial was 3.1% versus 3.4% in the warfarin group) but Pradaxa had about 50% more bleeding from the gastrointestinal tract and warfarin about 50% more bleeding into the brain.

Another big difference between the novel anticoagulants and warfarin is that we have antidotes (Vitamin K, fresh frozen plasma) that can reverse the anticoagulation state rapidly for warfarin but until recently none for the newer drugs. (There is now available an antidote for Pradaxa).  This information also was made very clear to all doctors prescribing the medications in the package insert and educational talks. Despite this, in the major trials comparing these newer agents to warfarin, the newer agents were as safe or safer than warfarin.

The most feared bleeding complication on all OACs is bleeding into the head (intracranial hemorrhage). The risk of ICH is between 0.2 to 0.4 percent per year on warfarin. Studies show with the NOACs the risk is about half of the risk on warfarin.

Should You Take a NOAC or Warfarin?

Once the decision has been made to start a blood thinner, the next question is whether to take warfarin or a NOAC. Warfarin (brand name Coumadin) has been utilized since the 1950s  and prior to 2010 was  the only drug available for doctors to reduce clot formation in the heart and susbsequent strokes.. Warfarin is only effective and safe within a narrow window and its effects are strongly influenced by Vitamin K in the diet and most medications. Thus, frequent blood testing and adjustment in dosage is needed, and close monitoring of diet and changes in medications. Even with this close monitoring, serious and sometimes fatal bleeding occurs frequently with warfarin.

Here is a patient information sheet on warfarin which gives you an idea of issues you will need to be aware of when taking the drug. (WArfar patient handout)

If you do a Google search on warfarin you will quickly discover that it is used as a rat poison. Scientists isolate the chemical from  sweet clover that was causing cows to bleed and then developed a more potent form that they named warfarin in the 1940s. After developing blood tests that allowed the drug to be used safely  to dissolve clots it was approved for human use in the 1950s.

Warfarin or more potent variations on its chemical structure have been utilized as rat poison since the 1940s.

The rats are consuming much larger quantities of the blood thinner and are clearly not being monitored for blood thinness.

Some despicable sites peddling alternative or natural products such as this “Healthy Habits” site engage in fear-mongering over the warfarin/rat poison connection in order to promote totally unproven products. Healthy Habits indirectly suggests  that Nattokinase : is a safer, more effective natural alternative to warfarin” This remarkable enzyme has the ability to dissolve blood harmful clots involved in heart disease and strokes without upsetting normal healthy clotting.”

Such misinformation is dangerous and could lead to patients stopping a life-saving medication and suffering a stroke.

By the way, in this Xarelto (another NOAC competitor) ad, Screen Shot 2016-06-29 at 2.21.20 PMKevin Nealon says he chose Xarelto over warfarin because he wanted to eat salads. This is a common misconception and the makers of Xarelto should be ashamed for promulgating it.

I tell my patients it is fine to eat green, leafy vegetables while taking warfarin. The Vitamin K in the vegetables does influence the effectiveness of warfarin thinning blood but this is why we check the blood test to determine the appropriate dosage of warfarin for you and your personal dietary Vitamin K consumption , be it high or low.

Novel Oral Anticoagulant Drugs

The newer OACs, in contrast to warfarin do not require blood tests for monitoring of their efficacy because their levels are not significantly influenced by changes in diet or most medications.

In head to head studies versus warfarin four of these NOACs have demonstrated at least similar efficacy in preventing stroke and at most similar bleeding risk.

Due to their perceived advantages most new prescriptions for OACs are for NOACs. In contrast to 2014 American afib guidelines which don’t state a preference, the most recent European afib guidelines recommend choosing a NOAC over warfarin when initiating anticoagulant therapy in patients who are eligible for NOACs. (Ineligible patients include those with mitral stenosis, mechanical heart valves and end-stage renal disease.)

The ESC guidelines published in 2016, , make choosing a NOAC over warfarin a IA recommendation. This means there is a consensus that the treatment should be recommended (Class I recommendation) and that there is strong evidence from randomized controlled trials to support it (Level A.)

I have decided to primarily use Eliquis (apixaban) as my NOAC of choice based on my comparison of the different NOAC studies. If a patient’s insurance covers another NOAC better , making it cheaper then  I am happy to switch.

Because these four NOACs are new and brand name they are significantly more expensive than warfarin. Cost varies substantially based on type of insurance coverage and we can only determine how much a patient will pay for any given NOAC based on writing a prescription and having a pharmacy check out the cost.

I have found some patients paying nothing for their NOAC whereas some are paying several hundred dollars monthly. The more NOACs cost, the more likely the patient and I are to choose warfarin.

While waiting to determine if cost is going to be prohibitive I will typically provide the patient with samples of the NOAC chosen. The pharmaceutical companies making these NOACs are clearly making substantial profits off them and they are happy to provide lots of samples to doctors to influence the doctors to utilize their product.

NOACs are being extensively promoted both to physicians and directly to patients. Physicians have to be especially careful to make sure they are presenting a true summary of the relative risks and benefits of warfarin versus NOACs in light of these constant attempts to influence them.

Despite now having four NOACs with similar benefits and ease of use compared to warfarin, the cost of these agents doesn’t seem to have declined significantly from when the first NOAC came on the market. Personally, I would love to see Medicare step in and negotiate significantly lower costs for American senior citizens.

An abstract at the ACC meeting in March of 2017 suggested  a reduction in medical costs with NOACs despite their high costs. This was related to a lower rate of major bleeding complications: Xarelto cost $542 per patient compared with warfarin’s $500, or $42 more. Pradaxa, cost $367 to warfarin’s $452, saving $85.  Eliquis cost  $286 charge against warfarin’s $537 resulting in $251 in savings. Data were from from a study of U.S. Medicare patient records.

Aspirin May Not  Prevent Stroke In Afib

Many patients consider aspirin to be  a “blood thinner” that has some benefit in preventing clots and strokes in patients with afib. However,  aspirin is not considered a blood thinner or anticoagulant and is more properly  termed an anti-platelet agent.

I used to consider aspirin at doses of 120 to 200 mg daily provided some protection against stroke in afib and put afib patients on aspirin who were low risk for stroke or would not or could not take OACs.

More and more, however, experts are reaching the conclusion that the substantial bleeding complications from aspirin usage outweigh its very slight benefit in stroke prevention.

The most recent ESC guidelines, in fact, list aspirin therapy for stroke prevention in atrial fibrillation as IIIA. That means that overall it is felt to be harmful (III) with a high level of evidence (A.)

Bleeding risks for aspirin are similar to warfarin and Eliquis. Thus, patients should not consider aspirin as a safer alternative to prevent stroke in afib.

Finally, do not take any “natural” supplement that has been promoted as a blood thinner. These are neither safe nor effective. Remember that it took years of scientific investigation and careful testing in animals then humans before warfarin (the agent in sweet clover that caused cows to bleed ) was transformed into a safe and effective anticoagulant.

Antiemboligenically yours

-ACP

Is Chocolate Good For The Heart?

While in Paris recently,  allegedly researching the French Paradox, the skeptical cardiologist and his Eternal Fiancee’ participated in a Food Tour (Paris By Mouth).  Along with 2 other American couples, we were guided and educated by a Parisian food/wine expert as we wandered from one small shop to another in the St. Germain district of the Left Bank.

We collected the perfect Baguette Monge from Eric Kayser, delicious rillettes, terrine, and saucisson from Charcuterie Saint Germain, amazing cheese from Fromager Laurent Dubois, delightful  pastries from Un Dimanche a Paris, and unique and delicious chocolate from Patrick Roger.

The tour ended at La Cave du Senat wine shop, where we descended into a stone cellar and tasted all of the delicious foods while drinking wonderful wines.

The French Paradox refers to the fact that the French are among the world’s highest consumers of saturated fat, but have among the world’s lowest rates of cardiovascular disease. For those nutritional experts still obsessed with the dangers of all saturated fats, this poses a conundrum.

Cheese And The French Paradox

France consumes more cheese (27 kg per person per year) than any other country in the world (the US only consumes 16 kg per capita). Unlike Americans who have embraced low fat or skim versions of cheese, the French predominantly consume full fat cheese.

I wrote In Defense of Real Cheese  in 2014 and extolled the heart-healthy virtues of eating full fat , non factory-processed cheese.

Perhaps the French are protected against heart disease by their high consumption and love of real cheese ?

Chocolate And The French Paradox

Whereas cheese contains saturated fat and has been unfairly stigmatized as unhealthy, chocolate, similarly with high saturated fat content, seems to have been coronated as the king of food that is yummy but paradoxically is also heart healthy.

Could chocolate be the enigmatic protector of the hearts of the French?

Back on Boulevard Saint-Germain we entered the shop of Patrick Roger, who won the coveted Meilleur Ouvrier de France, in the craft of chocolate in 2000. The MOF is France’s way of recognizing the best artisans in various fields and occurs every 4 years. The standards are so high that in 2015 none of the 9 chocolatier competitors were felt to merit receiving the award.

The French clearly take their chocolate seriously but they don’t top the international charts at per capita consumption.

The Swiss consume 20 pounds of chocolate per year, whereas the French and US are tied for 9th, consuming 9.3 and 9.5 lbs. (Infographic from Forbes

 

 

Chocolate And The Heart

I’ve been meaning to write a post on chocolate and the heart since my encounter with high end chocolatiers in Paris and Bruges, and especially since May when there was much fanfare over a Danish study showing less atrial fbrillation in high chocolate consumers.

A NYTimes piece stimulated by the Danish study and entitled “Why Chocolate May Be Good For The Heart” typified the media headlines  and summarized the study thusly:

Scientists tracked diet and health in 55,502 men and women ages 50 to 64. They used a well-validated 192-item food-frequency questionnaire to determine chocolate consumption.

After controlling for total calorie intake, smoking, alcohol consumption, body mass index and other factors, they found that compared with people who ate no chocolate, those who had one to three one-ounce servings a month had a 10 percent reduced relative risk for atrial fibrillation, those who ate one serving a week had a 17 percent reduced risk, and those who ate two to six a week had a 20 percent reduced risk.

Previous large, well done observational studies also show that high chocolate consumption compared to no consumption is associated with a lower risk of cardiovascular disease.

Of course these being observational studies with only weak (but significant) associations, we cannot conclude that chocolate consumption actually  lowers the risk of developing afib or cardiovascular disease (causation.)

My favorite graph to hammer home this point is below and plots how much each country consumes in chocolate, versus the number of nobel laureates.

 

 

 

 

 

 

 

 

 

There is a good correlation here (Pearson’s (no relation unfortunately) correlation coefficient or r value) which is highly significant (p value <.0001). But does anyone seriously think a country can boost its Nobel Laureate production by promoting chocolate consumption?

The authors of the Danish afib trial, admit the possibility of residual or unmeasured confounding variables as a limitation in their discussion:

Although we had extensive data on diet, lifestyle and comorbidities, we cannot preclude the possibility of residual or unmeasured confounding. For instance, data were not available on renal disease and sleep apnoea. However, after adjusting for age, smoking status and other potential confounders, the association was somewhat attenuated but remained statistically significant.

Most chocolate authorities proclaim the health  benefits of dark chocolate over milk chocolate but in this Danish study:

We did not have information on the type of chocolate or cocoa concentration. However, most of the chocolate consumed in Denmark is milk chocolate. In the European Union, milk chocolate must contain a minimum of 30% cocoa solids and dark chocolate must contain a minimum of 43% cocoa solids; the corresponding proportions in the USA are 10% and 35%.16 Despite the fact that most of the chocolate consumed in our sample probably contained relatively low concentrations of the potentially protective ingredients, we still observed a robust statistically significant association, suggesting that our findings may underestimate the protective effects of dark chocolate.

Despite the fact that the participants in the Danish AFib study were likely mostly consuming  milk chocolate rather than dark chocolate,  the lead author of the study has been quoted as saying “dark chocolate with higher cocoa content is better… because it is the cocoa, not the milk and sugar, that provides the benefit.”

The Chocolate-Industrial -Research Complex

Julia Volluz, in a nicely written piece at Vox  entitled “Dark chocolate is now a health food. Here’s how that happened.” describes how “over the past 30 years, food companies like Nestlé, Mars, Barry Callebaut, and Hershey’s— among the world’s biggest producers of chocolate — have poured millions of dollars into scientific studies and research grants that support cocoa science.”

Here at Vox, we examined 100 Mars-funded health studies, and found they overwhelmingly drew glowing conclusions about cocoa and chocolate — promoting everything from chocolate’s heart health benefits to cocoa’s ability to fight disease. This research — and the media hype it inevitably attracts — has yielded a clear shift in the public perception of the products.

“Mars and [other chocolate companies] made a conscious decision to invest in science to transform the image of their product from a treat to a health food,” said New York University nutrition researcher Marion Nestle (no relation to the chocolate maker). “You can now sit there with your [chocolate bar] and say I’m getting my flavonoids.”

Flavonols and Blood Pressure

Dark chocolate and cocoa products are rich in chemical compounds called flavanols. Flavanols have attracted interest as they might help to reduce blood pressure, a known risk factor for cardiovascular disease. The blood pressure-lowering properties of flavanols are thought to be related to widening of the blood vessels, caused by nitric oxide.

The latest Cochrane Review on this topic commented on the poor quality of the studies involved:

Studies were short, mostly between two and12 weeks, with only one of 18 weeks. The studies involved 1804 mainly healthy adults. They provided participants with 30 to 1218 mg of flavanols (average of 670 mg) in 1.4 to 105 grams of cocoa products per day in the active intervention group. Seven of the studies were funded by companies with a commercial interest in their results, and the reported effect was slightly larger in these studies, indicating possible bias.

This graph from Volluz’s Vox article demonstrates how much chocolate you would need to consume to get the average amount of flavanols that participants in these studies received:

The Cochrane review felt there was

moderate-quality evidence that flavanol-rich chocolate and cocoa products cause a small (2 mmHg) blood pressure-lowering effect in mainly healthy adults in the short term.

Thus, for a very small drop in blood pressure you would have to make chocolate the main source of calories in your daily diet.

Consuming such large amounts of chocolate, even dark chocolate, would drastically increase your sugar consumption.

Further weakening any conclusions on the benefit of chocolate are that these are very short-term studies with markedly different baseline BPs, ages, and large variations in flavanol dosage.

Is Your Chocolate Produced By Slaves?

After reading the Danish AFib article, I purchased several bars of Tony’s Chocolonely chocolate that caught my eye at the Whole Foods checkout counter. The bars had interesting wrappers and on the inside of the wrapper I discovered that Tony’s Chocolonely’s claim to fame is that it is “slave-free.”

Per Wikipedia:

Tony’s Chocolonely is a Dutch confectionery company focused on producing and selling chocolate closely following fair trade practices, strongly opposing slavery and child labour by partnering with trading companies in Ghana and Ivory Coast to buy cocoa beans directly from the farmers, providing them with a fair price for their product and combating exploitation.

The slogan of the company is: “Crazy about chocolate, serious about people“.

I was previously unaware of the problem of child slavery and cocoa production. If you’d like to read more about it start here.

The Tony’s Chocoloney was so tasty I ended up consuming vast quantities of it at the end of the day and it disappeared rapidly. Currently the skeptical cardiologist’s house is chocolate free.

Should Chocolate Be Considered A Super Food or A Slave Food?

I can’t recommend chocolate to my patients as a treatment for high blood pressure or to reduce their risk of heart attack or stroke on the basis of the flimsy evidence available.

If you like chocolate, the evidence suggests no adverse effects of consuming it on a regular basis.

As far as flavanols obtained from cocoa and their benefits for cardiovascular disease, I eagerly awaiit the result of the ongoing Cocoa Supplement and Multivitamin Outcomes Study (COSMOS), a randomized trial looking at whether daily supplements of cocoa extract and/or a standard multivitamin reduces the risk of developing cardiovascular disease and cancer.

Patients and readers should recognize that there is an ongoing research/media campaign by Big Chocolate to convince them that chocolate is a SuperFood which can also be a dessert.

Flavanoidly Yours,

-ACP