Tag Archives: afib

Why I Favor The Early Restoration and Maintenance of Sinus Rhythm In Most Patients With Atrial Fibrillation

When your heart stops beating synchronously and goes into atrial fibrillation all sorts of bad things begin happening. The normal mechanisms for controlling how fast your heart is beating are lost and in most individuals the rate accelerates inappropriately. The strength of the atria’s pumping force and the normal precise synchronization of the upper and lower chambers  deteriorates.

You might logically conclude then, that all efforts should be focused on converting the rhythm back to normal,  for in the normal rhythm the heart can go back to beating regularly, efficiently  and synchronously the way nature intended.

Maintenance of this normal (sinus) rhythm (NSR), presumably, will eliminate the high risk of clot formation and stroke associated with atrial fibrillation (AF) , prevent heart failure, and prolong life.

AF is abnormal. the thinking goes, and normality is the state in which we were born and to which we should seek to return.

Is Normal Sinus Rhythm Superior to Atrial Fibrillation?

It would be hard to find a cardiologist who doesn’t believe that patients are better off in NSR than AF but the more difficult question and more clinically relevant question is “if your heart has gone into atrial fibrillation will you do better in the long run with a strategy of trying to convert the rhythm back to normal and keep it there (which involves medications (anti-arrhythmic drugs) and/or procedures) versus just controlling the heart rate and letting the atria fibrillate to their heart’s content.

Unfortunately, studies that have compared the  strategy of maintaining NSR (rhythm control) with leaving the heart to fibrillate have not shown a benefit in preventing stroke or death in the patients randomized to rhythm control

To quote the 2016 European Society of Cardiology  guidelines on AF

Although many clinicians believe that maintaining sinus rhythm can improve outcomes in AF patients, all trials that have compared rhythm control and rate control to rate control alone (with appropriate anticoagulation) have resulted in neutral outcomes.

(see references for this below)

However, findings from these studies can only be applied to the population studied, thus younger patients without structural heart disease and patients over age 80, who combined constitute up to 50% of the AF group were not represented in these comparison studies.

The elderly are more dependent on normal atrial function for maintenance of cardiac output and are more likely to have issues with anticoagulation, thus they may benefit more from maintenance of NSR than the young.

In addition, much of the morbidity and mortality in these trials was related to failure to anticoagulate patients who were in NSR. The stroke risk persists in this group, we have learned, because they may not recognize when AF occurs. Therefore, most authorities recommend lifelong  anticoagulation for those who have had  AF and have significant risk factors for stroke whether they

These and other  reasons for the  failure of the so-called rhythm strategy have long been debated but most experts blame it on the absence of a safe and effective method for maintaining NSR: the drugs  and procedures (catheter ablations) we have used create their own problems and don’t always work.

Why Then, Do I And Most Cardiologists Recommend Efforts To Maintain Normal Sinus Rhythm?

This is a question almost no AF patients ask. It is quite easy for a treating cardiologist to invoke the “normality” of NSR and the dangers of AF and most AF patients require no more justification. But they really should demand a compelling rationale.

For those who feel badly in AF despite treatment with medications to keep the heart rate normal cardiologists can justify the efforts because we are making patients feel better

The ESC guideline summarizes this as follows

For now, rhythm control therapy is indicated to improve symptoms in AF patients who remain symptomatic on adequate rate control therapy.

However, there are important limitations to letting symptoms guide our approach.

For one, symptoms are in the mind of the patient and cannot be measured objectively. For another, the symptoms a patient experience could be from something other than AF.

You might think that we can objectively verify that symptoms are due to atrial fibrillation if they resolve after converting the patient to sinus rhythm but symptoms can be heavily influenced by the patient’s perception that something has been done to fix them. This placebo effect is well-known from clinical trials of medications but may be even more prominent after procedures.

It is not uncommon for me to perform a cardioversion on a patient , see the patient in follow-up in AF and have them tell me how tremendous they have felt since the cardioversion.

The difficulty of objective symptom measurement is one of many factors contributing to  a tremendous variability in how cardiologists approach rhythm control  for AF.

Some cardiologists have concluded that maintaining SR is rarely worth the trouble and they add rate controlling medications and anticoagulants and see the patient back once a year. Let’s call these NSR Nihilists

On the other end of the spectrum, cardiologists who are true believers in the value of NSR run their patients through multiple anti-arrhythmic drugs, cardioversions and ablations to achieve that goal. When this is done excessively such cardiologists become NSR Overtreaters.

I put myself somewhere in between the Nihilists and the Overtreaters and consider myself a rational NSR advocate or enthusiast but one who has a very clear understanding of the dangers of over treatment and who recognizes that many patients have done well for decades in permanent AF.

Recording and observation of symptoms depends heavily  on the recorder and observer: the Nihilists are loath to find symptoms attributable to AF whereas the Overtreater may see any and all symptoms as due to AF.

Like other areas in life and medicine we have to look closely at hidden motivations and conflicts of interest to fully understand variations in behavior.

If one were to analyze the financial benefit from testing and procedures to treating cardiologists I have no doubt that the Overtreaters are getting a lot more than the Nihilists.

In an ideal world, cardiologists would not benefit more financially based on what procedures they recommend be performed on their patients but this is not the reality.

Reasons For NSR Maintenance Beyond Symptoms

 I’ve mentioned two solid reasons for aggressively trying to maintain NSR in a previous post:

A second group of patients, I think, benefits the most from maintaining sinus rhythm (rhythm control strategy): patients who develop heart failure when they go into AF.

These patients may not even know they are in AF because they don’t feel the typical symptoms initially.  After a few days or weeks or months of being in afib silently, however, they develop shortness of breath, weakness and leg  swelling – classic signs of heart failure.

When we look at the heart of such a patient by echocardiography, we often find one of two things causing the heart failure: a weakening of the heart muscle (cardiomyopathy) or significant leakage/backflow from the mitral valve (mitral regurgitation). Following cardioversion and maintenance of SR for weeks to months, the heart muscle strengthens back to normal and/or the mitral regurgitation improves dramatically and the heart failure resolves.

The 2014 ACC guidelines for management of AF admit the lack of randomized trials supporting maintenance of NSR but cite several factors that would “favor attempts at rhythm control” with which I generally agree. These are:

  • difficulty in achieving adequate rate control,
  • younger patient age,
  • tachycardia-mediated cardiomyopathy,
  • first episode of AF,
  • AF precipitated by an acute illness
  • patient preference.

If, after discussion of the options, a patient decides they prefer no attempts at maintaining NSR,  I try to make them aware that AF begets AF. The longer they stay in AF the larger and more diseased their atria become and the harder it is to stay in NSR with any techniques. In other words, this not a decision that can easily be reversed a few years from now if they start feeling poorly.

The ACC guidelines put it this way:

AF progresses from paroxysmal to persistent in many patients and subsequently results in electrical and structural remodeling that becomes irreversible with time . For this reason, acceptance of AF as permanent in a patient may render future rhythm-control therapies less effective. This may be more relevant for a younger patient who wishes to remain a candidate for future developments in rhythm-control therapies. Early intervention with a rhythm-control strategy to prevent progression of AF may be beneficial.

Many of the factors cited for leaning toward NSR maintenance are, of course, soft and vague.  One doctor’s young patient is another doctor’s old patient. The definition of adequate rate control is unclear. What qualifies as an acute illness?

My Approach to Maintenance of NSR

I favor a more aggressive approach to maintenance of NSR. I justify this because in my experience with meticulous attention to detail and with close monitoring of patients on anti-arrhythmic drugs I have observed that most patients do better in the long run with NSR Than AF.

Over thirty years of managing patients with AF and comparing those who are left to permanently be in AF versus those who maintain NSR  I see substantial differences. Let me cite two case examples to buttress my argument.

A 75-year-old man with permanent atrial fibrillation came under my care after his cardiologist retired. He had been in AF with rate well controlled and on anticoagulation since 2008. He is active without any symptoms.

He had an echocardiogram in 2008 with the new onset of AF and it showed a normal sized left and right atria and no valvular problems.

Over 10 years,  however, the size of both his atria have dramatically increased. His current echo shows severe enlargement of his left atrium (LA volume index=72 cm3/M2) and right atrium (RA area=26 cm2). He has developed significant leakage (regurgitation)  from both his mitral and tricuspid valves.

afmrlae

This is the norm for most patients who have been in AF for a long time.

The larger the left atrium gets over time, the more dysfunctional it becomes and the more likely clots are to form in the LA appendage. Although anticoagulation dramatically reduces the formation of LA clots, patients frequently have to come off anticoagulation for surgeries, spine injections, bleeding and other issues.

Would you rather have a left atrium that has been maintained in NSR or one that is massively enlarged and dysfunctional if you have to stop your anticoagulation?

The other exam example is of a 74 year old man whose AF was detected at the time of a colonoscopy. When I saw him he was without symptoms with normal lab and cardiac testing. We attempted one cardioversion without anti-arrhythmic drugs and within two weeks he reverted back AF. He elected not to start any anti-arrhythmic drugs and repeat the cardioversion and was doing fine when I saw him 6 months later.

However, shortly after that visit he ended up in severe heart failure with severe left ventricular  dysfunction and severe mitral regurgitation at an outside hospital. This time he agreed with a more aggressive approach to maintenance of SR and after prolonged amiodarone loading and a repeat cardioversion he has maintained SR for 6 months. The function of his left ventricle has improved to near normal (LVEF has increased to 49%) and there is no significant leakage from his mitral valve.

Whereas, most patients who feel fine in AF and elect to stay in it do well there is an unpredictable but significant number who despite adequate rate control develop cardiomyopathy and valvular regurgitation with resulting heart failure.

Medical Maintenance of SR

Yes, I’m convinced that patients can safely and effectively be maintained in SR with medical therapy and the occasional cardioversion.

I try not to fall in the camp of Overtreaters but consider myself a Rational Normal Sinus Rhythm Enthusiast and Advocate.

In my practice when atrial fibrillation reaches a point that requires addition of an anti-arrhythmic medication  I predominantly utilize two such drugs: amiodarone and flecainide.

Patients with structurally  normal hearts do well with flecainide and those with structural heart disease (heart failure, left ventricular hypertrophy, or significant coronary artery disease ) do well with amiodarone when they are monitored closely by a cardiologist with extensive experience using the drugs.

I’ll talk about each of these options  as well as cardiac ablation in detail in subsequent posts.

Antifibrillatorily Yours,

-ACP

Six studies showing no difference in outcomes between rhythm and rate control strategies.

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.

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.

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

What Is Behind The Significant Changes In AliveCor’s Kardia Mobile ECG App?

The Skeptical Cardiologist is a strong proponent of empowering patients with atrial fibrillation by utilizing personal cardiac rhythm devices such as Afib Alert or AliveCor’s Kardia.

I’ve written about my experiences with the initial versions of the Kardia mobile ECG device and the service it provides here and here.

I have been monitoring dozens of my afib patients using AliveCor’s Physician Dashboard.

Recently AliveCor changed fundamentally the way their app works such that for new users much of the functionality I described in my previous posts now requires subscribing to their Premium service which costs $9.99 per month or $99 per year.

What Has Changed With The Kardia App

The Kardia device which works with both iOs and Android smart
phones is unchanged and still generates a “medical-grade” single lead rhythm strips which appears within the Kardia app.

Screenshot from AliveCor’s website showing the Kardia recording device being utilized with the obtained  typical ECG recording displayed on the smartphone app.

 

 

The app still is reasonably accurate at identifying atrial fibrillation or normal heart rhythms and offers a fee-based service for interpretation of unclassified ECGs.

However, for new purchasers of Kardia,  the capability to access, email or print prior ECG recordings has gone away. Prior to March of this year, Kardia users could access prior ECG tracings which were stored in the cloud  by touching the “Journal” button on the app. These older tracings could be emailed and they were available through the cloud for a physician like myself to review at any time.

Now new Kardia purchasers will find that when they make an ECG recording they have the option to email a PDF of the ECG but once they hit the DONE button it is gone and is not stored anywhere.

For my patients purchasing after March, 2017 this means that unless they  purchase Kardia Premium service I will not be able to view their ECG recordings online.

An AliveCor account executive summarized for me the changes as follows:

We added a significant number of features over the past year and a half, and grandfathered all users on March 16th, 2017. New users now have the option to download and use Kardia for free, but the premium services are $9.99/mo or $99/year. Kardia Premium allows unlimited storage and history of their EKGs, summary reports with longitudinal data, blood pressure monitoring and tracking weight and medication.

Why Journal Functionality Is Important

If you purchased your AliveCor/Kardia device prior to March 16th, 2017 ago the journal  functionality still works. Let’s call such customers “Journal Grandfathered”.

This Journal functionality is important in a number of ways:

  1. My Journal Grandfathered patients can bring their phones with them during an office visit and we can review all of their ECG tracings.
  2. Journal gGandfathered Kardia users can email their old tracings to their physicians or to anyone they wish (even the skeptical cardiologist!). They can also print them out and save PDFs of the tracings.
  3. I  can view through my online physician account all of my Journal Grandfathered patients. This means any time a patient of mine makes a recording that is unclassified or suggests atrial fibrillation I can be notified and immediately view it online.

This fundamental change took place as AliveCor attempts to convince  purchasers of the Kardia device to use their Premium service.

Why AliveCor Changed The Kardia App Function

Dr. David Albert, inventor and  cardiologist and the founder of AliveCor was kind enough to talk with me about this change.

He indicates that of the 150,000 AliveCor users, 10,000 are now using the Kardia Premium service. About 20% of new users elect Kardia Premium.

Prior to the change all AliveCor users had their old ECG recordings stored in the cloud in a HIPPA compliant fashion. This free service was costing AliveCor quite a bit and the company felt it was best to switch to a subscription service to provide this secure cloud storage.

With the change to the (relatively inexpensive)  subscription service, patients will get additional features. As the AliveCor account executive described:

Kardia Premium allows unlimited storage and history of their EKGs, summary reports with longitudinal data, blood pressure monitoring and tracking weight and medication.

 

 

I’ve looked at the Premium service and it seems quite useful when combined with a connected physician utilizing Kardia Pro.  I’ll evaluate the Premium service and the physician Kardia Pro service  further and write a full post on its features in the near future.

If you are not grandfathered and want to stick with the Basic Kardia service you still have an immensely useful and  inexpensive device which allows personal detection of your cardiac rhythm. Just remember to email yourself the ECG recording you just made before you hit DONE.

Nonarrhythmically Yours,

-ACP

Why Did I Go Into Atrial Fibrillation?

The skeptical cardiologist is asked this  question or  variations of it (such as  what caused me to go out of rhythm?) on a daily basis.

Most patients would like to have a reason for why their atria suddenly decided to fibrillate.  It’s understandable. If they could identify the reason perhaps they could stop it from happening again.

There are two variations on this question:

For the patient who has just been diagnosed with afib the question is really “what is the underlying reason for me developing this condition?”

For the patient who has had afib for a while and it comes and goes seemingly randomly the question is “what caused the afib at this time? i.e. what triggers my episodes?”

For most patients, there is no straighforward and simple answer to either one of these questions

The Underlying Cause of Atrial Fibrillation

My stock response to this first question goes like this:

“Atrial fibrillation is associated with getting older and having high blood pressure. 10 % of individual >/= 80 years have atrial fibrillation. 90% of patients with afib have hypertension.

Aging and hypertension may increase scarring or damage in the left atrium or pulmonary veins that drain into the left atrium setting up abnormal electrical signals.

There are some specific things that cause afib and we will be doing a complete history and physical and some testing to check for the most common. We’ll check you for thyroid or electrolyte abnormalities and we will do an echocardiogram to look for any structural problems with your heart.

If we do find a treatable cause such as hyperthyroidism or a cardiac valve problem we will fix that and the afib may go away, however chances are we won’t find a specific reason why you developed atrial fibrillation.

Finally, and possibly most importantly, let’s take a close look at your lifestyle. Are you overweight? If so, losing 10% of your body weight will substantially lower your risk of recurrent atrial fibrillation. Let’s get you exercising regularly and eating a healthy diet, Make sure your sleep is optimized and your stress minimized.”

If you’d like a more sophisticated look into what causes afib take a look at this graphic from a recent paper.

Current theory has it that factors that we know are associated with atrial fibrillation  including obesity, hypertension and sleep apnea cause atrial structural abnormalities or remodeling which then create various atrial electrical abnormalities.

 

Exhaustive List of Causes

If you’d like an exhaustive list of factors associated with atrial fibrillation, you can memorize the acronym P.I.R.A.T.E.S. which is sometimes used by medical students to remember the causes of atrial fibrillation which include:

  • Pulmonary disease (COPD, PE)/Phaeochromocytoma
  • Ischemia (ACS)
  • Rheumatic heart disease (mitral stenosis)
  • Anemia (high output failure/tachycardia)/Atrial myxoma/Acid-base disturbance
  • Thyrotoxicosis (tachycardia)
  • Ethanol/Endocarditis/Electrolyte disturbance (hypokalaemia, hypomagnesaemia)/Elevated BP
  • Sepsis/Sick Sinus Syndrome/Sympathomimetics (Drugs)

And here’s a cute  mnemonic from the Family Practice Notebook using ATRIAL FIB itself (although you have to use the ph of pheochromocytoma to make the f of fib)

  1. Alcohol Abuse
  2. Thyroid Disease
  3. Rheumatic Heart Disease
  4. Ischemic Heart Disease
  5. Atrial Myxoma
  6. Lung (Pulmonary Embolism, Emphysema)
  7. Pheochromocytoma
  8. Idiopathic
  9. Blood Pressure (Hypertension)

Both of these mnemonics are a little outdated. For example, rheumatic mitral stenosis is quite rare as a cause of afib in the US but  degenerative and functional mitral regurgitation is a common cause.

Ischemic heart disease (aka coronary heart disease) isn’t felt to cause atrial fibrillation unless it results in a myocardial infarction and subsequent heart failure. Way too many cardiac catheterizations are performed on patients who present with atrial fibrillation by doctors who don’t know this.

Congenital heart defects (not mentioned in either mnemonic) especially atrial septal defects often are associated with afib

There may be case reports of pheochromocytoma (a catecholamine-secreting neuroendocrine tumor) causing afib but they are few and far between.

Finally, genetics clearly play a role in the younger patient with afib without any known risk factors. One of my patients and his twin brother both developed symptomatic afib in their 40s.

In The Chronic Afibber What Triggers An Episode?

Alas, for most afibbers we won’t identify specific reasons why you go in and out of afib although there are some triggers you should definitely avoid such as excessive alcohol.

Some of the “causes” listed in the mnemonic are acute triggers of afib episodes.

For example low potassium or magnesium (typically induced by diuretics, diarrhea or vomiting) can bring on episodes .(See my discussion on potassium and PVCS here-much of it is relevant to afib.)

And I  have definitely seen patients go  into atrial fibrillation who have acute pulmonary problems such as pneumonia, pulmonary embolism or exacerbation of COPD.  In these cases, it is felt that the lung process raises pressure in the pulmonary arteries thereby  putting strain on the right heart leading to higher right atrial pressures.

Sleep apnea is associated with afib and I have had a few cases where after identifying that a patient’s  afib always began during sleep we were able to substantially lower episodes by treatment of sleep apnea.

Pericarditis with inflammation adjacent to the left atrium not uncommonly causes  afib. This is the likely mechanism for the afib that occurs frequently after cardiac surgery. Since pericarditis may never recur (especially in the cardiac surgery patient) we think the risk of afib recurring is low in these patients.

Anything that raises stress and stimulates the sympathomimetic nervous system can be a trigger. For example, a young and otherwise healthy patient of mine went into afib after encountering a car in flames along the side of the road. We found that beta-blockers (which block the sympathetic nervous system) helped prevent her episodes.

Some patients have odd but reproducible triggers. One of my patients routinely went into afib when he ate ice cream. I had a simple , very effective treatment plan for him.

Caffeine and Chocolate

Many afibbers have been told to avoid caffeine but a recent study of 34,000 women found that there was no increased risk of afib with increasing caffeine content and no sign that any of the individual contributors to caffeine in the diet (coffee, tea, cola, and chocolate) were more likely to cause afib.

Higher chocolate consumption, in fact, has recently been linked to a lower rate of afib. An observational  study of 55 thousand Danish men and women found that those who consumed 2 to 6 servings per week of 1 oz (30 grams) of chocolate had a 20% lower rate of clinically apparent afib.

Alcohol and Atrial Fibrillation

Binge drinking has long been known to cause acute atrial fibrillation.

However, it appears that even light to moderate chronic alcohol consumption increases the risk of going into atrial fibrillation.

This graphic from an excellent recent review of the topic gives the potential mechanisms:

The review concludes that although light to moderate alcohol consumption lowers your risk of dying, any alcohol consumption increases your risk of afib.

This graph shows the relationship between dying from heart disease (red line) and risk of going into afib (blue line) and amount of alcohol consumed.

Looking at the 15 drinks per week point on the x-axis (about 2 drinks per day) we see that your CV mortality is reduced by 20% whereas your risk of afib has increased by 20%.

A better point on the x-axis is 7 (1 drink per day) which has a 25% lower CV mortality but only a 10% higher risk of afib.

Whatever caused you to go into afib the good news is that with lifestyle changes and the care of a good cardiologist chances are excellent that you can live a normal, happy, healthy , long and active life.

Etiologically Yours,

ACP

 

Is September Really National Atrial Fibrillation Awareness Month (And Why Does It Matter?)

The skeptical cardiologist received an email from a woman telling him that September is atrial fibrillation awareness month and offering me the free use of an infographic given that I

“care deeply about helping people living with AF.”

Well, I do care about deeply about people living with atrial fibrillation and pretty much all cardiac diseases  (except perhaps Schuckenbuss syndrome.)

That’s the major reason I write this blog. I’ve written a lot about Afib and have a lot more i want to write (I really want to write about antiarrhythmic drugs, i.e. drugs that maintain you in normal sinus rhythm.)

But I don’t find it particularly helpful to assign a disease to a month or a day so my posts on atrial fibrillation come out randomly dependent on the mysterious machinations of my messy mind.

It turns out that September, 2009 was declared National Atrial Fibrillation Awareness Month (NAFAM) by Senate Resolution 262 although Stop Afib.org wants us to believe September is eternally NAFAM.

However, the email prompted me to better organize my atrial fibrillation and stroke page (now containing all that I have written on the subjects) which I have copied below.

Posts on Diagnosing Atrial fibrillation

Take your pulse and prevent a stroke

TIAs and silent atrial fibrillation. Sometimes strokes present in unusual ways, like the inability to differentiated a spade from a diamond when playing bridge and afib is often the cause.

Estimating Stroke Risk in Patients With Atrial Fibrillation You can estimate your stroke risk using an app that utilizes the CHAD2DS2-VASc score. I prefer to call the Lip score.

Posts About Using Personal Devices To Diagnose Atrial Fibrillation

Two That Work Reasonably Well

AliveCor

Using a Smart Phone Device and App To Monitor Your Pulse for Atrial Fibrillation (AliveCor)

AliveCor Is Now Kardia and It Works Well At Identifying Atrial Fibrillation At Home And In Office

AliveCor Successes and Failures.

Sustained Atrial Fibrillation or Not: The Vagaries and Inaccuracies of AliveCor/Kardia and Computer Interpretation of ECG Rhythm

AfibAlert

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

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

And One of Several Devices To Avoid: AF Detect

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

Posts About Treatment Of Atrial Fibrillation

        Lifestyle Changes

How Obesity Causes Atrial Fibrillation in FatSheep and How Losing Weight helps prevent afib from coming back.

Drug Therapy: Rate Control and Anticoagulation

Foxglove Equipoise. When William Withering began treating patients suffering from dropsy in 1775 with various preparations of the foxglove plant he wasn’t sure if he would help or hurt them. After 240 years of treatment, we are still unsure if the drug obtained from foxglove is useful.

Should Digoxin Still Be Used in Atrial Fibrillation? Recent studies suggest that we should not.

Why Does the TV Tell Me Xarelto Is A BAD Drug? Anticoagulant drugs that prevent the bad clots that cause stroke also increase bleeding risk. A bleeding complication is not a valid reason to sue the manufacturer.  The lawsuit are strictly a money-making tactic for sleazy lawyers.

Cardioversion and Ablation

Cardioversion: How Many Times Can You Shock The Heart?

Ablation: Cautionary Words From Dr. John Mandrola and The Wisdom of a Team Approach

Miscellaneous Topics

What Happens If You Go Into Atrial Fibrillation On A Cruise?

Infographics

Are infographics really helpful? Someone should do a study on that. Perhaps we could use the money we spend on infographics in atrial fibrillation to research whether the left atrial appendage should be excised at the drop of a hat.

Here’s the infographic (because everyone loves an infographic!)

The first part lays out the problem of AF with patriotic bunting.

The second part uses the annoying numerical infographic approach.

 

 

 

 

 

 

 

The third part explains why I got the email. A product is being promoted. The woman who sent me the email works for MyTherapyApp.

 

 

 

Eagerly Awaiting Schuckenbuss Syndrome Day,

-ACP

 

 

 

AliveCor (Kardia) Has A Premature Beat Problem: How PVCs and PACs Confuse The Mobile ECG Device

The skeptical cardiologist has many patients who are successfully using their AliveCor/Kardia devices to monitor for episodes of atrial fibrillation (afib).

However, a significant number of patients who have had atrial fibrillation also have premature beats. Sometimes patients feel these premature beats as a skipping or irregularity of the heart beat. Such palpitations  can mimic the feeling patients get when they go into atrial fibrillation.

The ideal personal ECG monitor, therefore,  would be able to reliably differentiate afib from premature beats for such patients.

Premature Beats: PVCs and PACs

I’ve discussed premature ventricular contractions (PVCs) here and here.  Premature beats can also originate from the upper chambers of the heart or atria.

Such  premature atrial contractions (PACs) have generally been considered benign in the past but a recent study showed that frequent (>30 s per hour) PACs  or runs of >20 PACs in a row were associated with a doubling of stroke risk.

For patients who experience either PVCs or  PACs the AliveCor device is frequently inaccurate.

PACs Misdiagnosed As Atrial Fibrillation

Here is a panel of recordings made by a patient of mine who has had documented episodes of atrial flutter in the past and who monitors his heart rhythm with Alivecor regularly:

Of the ten recordings , four were identified as “possible atrial fibrillation.”

Unfortunately only one of the four “possible atrial fibrillation” recordings has any atrial fibrillation: this one has 7 beats of afib initially then changes to normal sinus rhythm (NSR).

The other 3 recordings identified by AliveCor as afib are actually normal sinus rhythm with premature beats.

The first 3 beats are NSR. Fourth beat is a premature beat

In addition, frequently for this patient AliveCor yields an “Unclassified” reading for NSR with PACs as in this ECG:

PVCs Misread As Atrial Fibrillation

I wrote about the first patient I identified in my office who had frequent PVCs which were misdiagnosed by AliveCor as afib here.

Since then, I’ve come across a handful of similar misdiagnoses.

One of my patients began experiences period palpitations 5 years after an ablation for atrial fibrillation. He obtained an AliveCor device to rec  ord his rhythm during episodes.

For this patient,, the AliveCor frequently diagnoses “possible atrial fibrillation” but  all of his episodes turn out not to be afib. In some cases he is having isolated PVCs:

The first 3 beats in the lower strip are NSR. The fourth beat (purpose circle) is a PVC. AliveCor interpreted this as afib

At other times he has periods of atrial bigeminy  which are also called afib by AliveCor. In this tracing he has atrial bigeminy and a PVC.

 

 

PVCs Read As Normal

Premature beats sometimes are interpreted by AliveCor as normal. A reader sent me a series of  recordings he had made when feeling his typical palpitations. all of which were called normal. Indeed, all of them but one showed NSR. However on the one below the cause of his palpitations can be seen: PVCs.

The NSR beats (blue arrows) followed at times by PVCs (red arrows))

I obtained the “Normal”  tracing below from a patient in my office with a biventricular pacemaker and frequent PVCs who had no symptoms.

Paced beats (blue arrows) PVCs (red arrows)

PVCs Read As Unclassified 

A woman who had undergone an ablation procedure to eliminate her very frequent PVCS began utilizing AliveCor to try to determine if she was having recurrent symptomatic PVCs. She became quite frustrated because AliveCor kept reading her heart rate at 42 BPM and giving her an unclassified reading.

AliveCor is always going to call rhythms (other than afib) unclassified when it counts a  heart rate less than 50 BPM or greater than 100 BPM.

In this patient’s case, every other beat was a PVC (red circles). Her PVCs are sufficiently early and with low voltage so the AliveCor algorithm cannot differentiate them from T Waves and only counts the normal sinus beats toward heart rate.

Accurate AliveCor Readings

I should point out that many of my patients get a very reliable assessment from their devices. These tracings from a woman with paroxysmal atrial fibrillation  are typical: all the Normal readings are truly normal and all the atrial fibrillation readings are truly atrial fibrillation with heart rates  above 100.

AliveCor’s Official Position on Premature Beats

The AliveCor manual states

The Normal Detector in the AliveECG app notifies you when a recording is “normal”.  This means that the heart rate is between 50 and 100 beats per minute, there are no or very few abnormal beats, and the shape, timing and duration of each beat is considered normal.

What qualifies as “very few” abnormal beats is not clear. The manual goes on to state that the AliveCor normal detector has been designed to be conservative with what it detects as normal.

What is clear is that premature beats  significantly confuse the AliveCor algorithm. Both PVCs and PACs can create a false positive diagnosis of atrial fibrillation when it is not present.

Consequently, if you have afib and premature beats you cannot be entirely confident that a reading of afib is truly afib. Strongly consider having the tracing reviewed by a cardiologist before concluding that you had afib.

On the other hand if you are experiencing palpitations and make a recording with Alivecor that comes back as normal do not assume that your heart rhythm was totally normal. While highly unlikely to be afib, your palpitations could still be due to PACs or PVCs.

If a patient of mine has an abnormal or questionable AliveCor recording it is currently a very simple process for me to review the recording online  through my AliveCor doctor dashboard. The recordings can also be emailed to me.

However, Kardia appears to be trying to move new AliveCor purchasers to a subscription or Premium service. In addition, Kardia keep giving me messages that “the doctor dashboard is going away.”

Coralively Yours,

-ACP

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

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

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

Normal/Normal

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

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

 

Normal by AFA/Unreadable or Unclassified by AliveCor

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

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

Chaput AFA SR

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

GC Unclassified

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

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

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

 

False Positives

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

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

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

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

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

 

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

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

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

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

Screen Shot 2017-05-06 at 11.47.37 AM

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

Screen Shot 2017-05-06 at 11.49.49 AM

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

AFA Mcgill AF

 

 

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

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

 

 

Accuracy in Patients In Atrial Fibrillation

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

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

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

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

Screen Shot 2017-05-06 at 11.35.40 AM

ACK correctly identified the rhythm as AF

Screen Shot 2017-05-06 at 11.37.51 AM

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

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

 

 

Overall Accuracy

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

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

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

 

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

Summary

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

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

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

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

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

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

-ACP