Many patients (and perhaps physicians) are confused as to how best to utilize personal ECG devices. I received this question illustrating such confusion from a reader recently:
I first came across your website a year ago during persistent angina attacks, and returning now due to increasing episodes of symptoms akin to Afib. I bought a Kardia 2 yrs ago for the angina episodes, and looking to buy the Apple Series 4 for the Afib, as I want to try a wearable for more constant monitoring. What I would greatly appreciate if you had a basic guide for both the Kardia & Apple devices, specifically when and how to best employ them for unstable angina and detecting undiagnosed Afib. As in, what can I as a patient provide to you as a doctor for diagnosis in advance of a formal visit. I’m a US Iraq vet medically retired in the UK, and most of my concerns get dismissed out of hand as “anxiety”, not sure why they thought a stent would cure my anxiety though
First. please understand that none of these devices have any significant role in the management of angina. Angina, which is chest/arm/jaw discomfort due to a poor blood supply to the heart muscle cannot be reliably diagnosed by the single lead ECG recording provided by the Apple Watch, the Kardia Band or the Kardia mobile ECG device. Even a medical-grade 12 lead ECG doesn’t reliably diagnose angina and we rely on a constellation of factors from the patient’s history to advanced testing to determine how best to manage and diagnose angina.
Second, as you are having episodes “akin to Afib”, all of these devices can be helpful in determining what your cardiac rhythm is at the time of the episodes if they last long enough for you to make an ECG recording.
The single lead ECG recording you can make from the Apple Watch, the Kardia Band and from the Kardia mobile device can very reliably tell us what the cardiac rhythm was when you were feeling symptoms.
The algorithms of these devices do a good job of determining if the rhythm Is atrial fibrillation. Also, if the rhythm is totally normal they are good at determining normality.
These tracings can be reviewed by a competent cardiologist to sort out what the rhythm really is.
In all of these cases, having an actual recording of the cardiac rhythm at the time of symptoms is immensely helpful to your doctor or cardiologist in determining what is causing your problems.
My recommendation, therefore, would be to make several recordings at the time of your symptoms. Print them out and carefully label the print-out with exactly what you were feeling when it was recorded and present these to the doctor who will be reviewing your case.
As I’ve mentioned in previous posts (see here), my patients’ use of Kardia with the KardiaPro online service has in many cases taken the place of expensive and inconvenient long term monitoring devices.
Case Example-Diagnosing Rare And Brief Attacks Of Atrial Fibrillation
I recently saw a patient who I think perfectly demonstrates how useful these devices can be for clarifying what is causing intermittent episodes of palpitations-irregular, pounding, or racing heart beats.
She was lying on a sofa one day when she suddenly noted her heart “pumping fast” and with irregularity. The symptoms last for about an hour. She had noticed this occurred about once a year occurring out of the blue.
Her PCP ordered a long term monitor, a stress test and an echocardiogram.
The monitor showed some brief episodes of what I would term atrial tachycardia but not atrial fibrillation but the patient did not experience one of her once per year hour long episodes of racing heart during the recording. Thus, we had not yet solved the mystery of the prolonged bouts of racing heart.
She was referred to me for evaluation and I recommended she purchase an Alivecor device and sign up for the KardiaPro service which allows me to view all of her recordings online. The combination of the device plus one year of the KardiaPro service costs $120.
She purchased the device and made some occasional recordings when she felt fine and we documented that these were identified as normal by Kardia. For months nothing else happened.
Then one day in April she had her typical prolonged symptom of a racing heart and she made the recording below (She was actually away from home but had the Kardia device with her.)
When she called the office I logged into my KardiaPro account and pulled up her recordings and lo and behold the Kardia device was correct and she was in atrial fibrillation at a rate of 113 BPM.
With the puzzle of her palpitations solved we could now address proper treatment.
Continuous Monitoring for Abnormal Rhythms
Finally, let’s discuss the wearables ability to serve as a monitor and alert a patient when they are in an abnormal rhythm but free of any symptoms.
My reader’s intent was to acquire a device for “constant monitoring”:
I’m looking to buy the Apple Series 4 for the Afib, as I want to try a wearable for more constant monitoring.
This capability is theoretically available with Apple Watch 4’s ECG and with the Kardia Band (using SmartRhythm) which works with Apple Watch Series 1-3.
However, I have not been impressed with Apple Watch’s accuracy in this area (see here and here) and would not at this point rely solely on any device to reliably alert patients to silent or asymptomatic atrial fibrillation.
In theory, all wearables that track heart rate and alert the wearer if the resting heart rates goes above 100 BPM have the capability of detecting atrial fibrillation. If you receive an alert of high HR from a non ECG-capable wearable you can then record an ECG with the Kardia mobile ECG to see if it really is atrial fibrillation.
At 99$, the Kardia is the most cost-effective way of confirming atrial fibrillation for consumers.
I hope this post adds some clarity to the often confusing field of personal and wearable ECG devices.
The results of the Apple Heart Study, were presented this morning at the American College of Cardiology Scientific Sessions amid intense media scrutiny. The AHS is a “prospective, single arm pragmatic study” which had the primary objective of measuring the proportion of participants with an irregular pulse detected by the Apple Watch who turn out to have atrial fibrillation on subsequent ambulatory ECG patch monitoring.
I and over 400,000 other Apple Watch owners participated in the AH study by downloading the Apple Heart Study app and self-verifying our eligibility.
My assessment is that we have learned little to nothing from the AHS that we didn’t already know. I’m also concerned that many patients suffered anxiety or unnecessary testing after being referred to urgent care centers, emergency departments, cardiologists or primary care providers and the results of these inappropriate referrals may never be determined.
Here is the study in a nutshell:
Participants enrolled by submitting information using the iPhone Heart Study app and none of their isubmitted nformation was verified.
An irregular pulse notification was issued to 0.5% of participants who were then contacted and asked to participate in a Telehealth visit with a doctor (who we will call Dr. Appleseed)
Only 945 of the 2161 who received a pulse notification participated in the first study visit.
Interestingly, Dr. Appleseed was empowered to send participants to the ER if they had symptoms (chest pain, shortness of breath, fainting/losing consciousness) It is not clear how many were sent to the ER and what their outcomes were but this flow diagram shows that 20 were excluded from further testing due to “emergent symptoms.”
Another 174 participants were excluded after finding out at the first visit that they had a history of afib or aflutter and 90 due to current anticoagulant use (both of these factors were exclusion criteria which gives us an idea of how accurate the information was at the time of participant entry.)
After all these exclusions only 658 ECG monitor patches were shipped to the participants of which only 450 were returned and analyzed.
This means of the original 2161 participants who were notified of pulse irregularity, the study only reports data on 450 or 21%. Such a low rate of participation makes any conclusions from the study suspect.
Of the 450 ECG patches analyzed only 34% were classified as having afib. Only 25% of this afib lasted longer than 24 hours.
After the patch data was analyzed, patients had a second Telehealth visit with Dr. Appleseed who reviewed the findings with the patient. Per the initial published description of the methods of the AHS (see here) Dr. Appleseed would tell the participant to head to the ER if certain abnormalities were found on the ECG.
Per the study description (apple heart study), Dr. Appleseed recommended a visit to the PCP for “AF or any other arrhythmia” detected by the patch:”
“If AF or any other arrhythmias have been detected in reviewing the ambulatory ECG monitor data, or if there are other non-urgent symptom identified by the study physician during the video visit that may need further clinical evaluation, the Study Telehealth Provider directs the participant to his or her primary health care provider”
At this point it seems likely that a lot of participants were instructed to go see their PCPs. Because as someone who looks at a lot of 2 week ambulatory ECG recordings I know that is the rare recording that does not show “other arrhythmias.”
Even more distressing is the call that participants would have received based on “the initial technical read:” I’m presuming this “technical read” was by a technician and not by a cardiologist. In my experience, many initial reads from long term monitors are inaccurate.
“If the initial technical read identifies abnormalities that require urgent attention (ventricular tachycardia or ventricular fibrillation, high-degree heart block, long pauses, or sustained and very rapid ventricular rates), then the participant is contacted immediately and directed to local emergency care or advised how to seek local emergency care.”
I wonder how many ERs had AHS participants show up saying they had been told they had a life-threatening arrhythmia? How much down stream testing with possible invasive, life-threatening procedures such as cardiac catheterization were performed in response to these notifications?
Overall, these findings add nothing to previous studies using wearable PPG technology and they certainly don’t leave me with any confidence that the Apple Watch is accurately automatically detecting atrial fibrillation.
Was more harm than good done by the Apple Heart Study?
We will never know. The strength of this study, the large number of easily recruited participants is also its Achilles heel. We don’t know that any information about the participants is correct and we don’t have any validated follow up of the outcomes. In particular, I’m concerned that we don’t know what happened to all of these individuals who were sent to various health care providers thinking there might be something seriously wrong.
Perhaps Apple and Stanford need to review the first dictum of medicine: Primum Non Nocere, First Do No Harm.
Apple claims that its Apple Watch can detect atrial fibrillation (AF) and appropriately notify the wearer when it suspects AF.
This claim comes with many caveats on their website:
Apparently it needs to record 5 instances of irregular heart beat characteristic of atrial fibrillation over at least 65 minutes before making the notification.
This feature utilizes the watch’s optical heart sensors, is available in Apple Watch Series 1 or later and has nothing to do with the Apple Watch 4 ECG recording capability which I described in detail in my prior post.
Failure To Detect AF
A patient of mine with known persistent AF informed me yesterday that she had gone into AF and remained in it for nearly 3 hours with heart rates over 100 beats per minute and had received no notification. She confirmed the atrial fibrillation with both AW4 recordings and AliveCor Kardia recordings while she was in it.
The watch faithfully recorded sustained heart rates up to 140 BPM but never alerted her of this even though the rate was consistently over her high heart rate trigger of 100 BPM.
The patient had set up the watch appropriately to receive notifications of an irregular rhythm.
Reviewing her tracings from both the AW4 and the Kardia this was easily diagnosed AF with a rapid ventricular response.
What does Apple tell us about the accuracy of the Apple Watch AF notification algorithm? All we know is the unpublished , non peer-reviewed data they themselves collected and presented to the FDA.
In a study of 226 participants aged 22 years or older who had received an AFib notification while wearing Apple Watch and subsequently wore an electrocardiogram (ECG) patch for approximately 1 week, 41.6% (94/226) had AFib detected by ECG patch. During concurrent wear of Apple Watch and an ECG patch, 57/226 participants received an AFib notification. Of those, 78.9% (45/57) showed concordant AFib on the ECG patch and 98.2 % (56/57) showed AFib and other clinically relevant arrhythmias. These results demonstrate that, while in the majority of cases the notification will accurately represent the presence of AFib, in some instances, a notification may indicate the presence of an arrhythmia other than AFib. No serious device adverse effects were observed
This tells us that about 80% of notifications are likely to be Afib whereas 20% will not be Afib. It is unclear what the “other clinically relevant arrhythmias” might be. If I had to guess I would suspect PVCS or PACS which are usually benign.
If 20% of the estimated 10 million Apple Watch wearers are getting false positive notifications of afib that means 2 million calls to doctor or visits to ERs that are not justified. This could be a huge waste of resources.
Thus the specificity of the AF notification is 80%. The other important parameter is the sensivitiy. Of the cases of AF that last >65 minutes how many are detected by the app?
Apple doesn’t seem to have any data on that but this obvious case of rapid AF lasting for 3 hours does not give me much confidence in their AF detection algorithms.
They do have a lot of CYA statements indicating you should not rely on this for detection of AF:
It is not intended to provide a notification on every episode of irregular rhythm suggestive of AFib and the absence of a notification is not intended to indicate no disease process is present; rather the feature is intended to opportunistically surface a notification of possible AFib when sufficient data are available for analysis. These data are only captured when the user is still. Along with the user’s risk factors, the feature can be used to supplement the decision for AFib screening. The feature is not intended to replace traditional methods of diagnosis or treatment.
My patient took her iPhone and Apple Watch into her local Apple store to find out why her AF was not detected. She was told by an Apple employee that the Watch does not detect AF but will only notify her if her heart rate is extremely low or high. I had asked her to record what they told her about the problem.
As I’ve written previously (see here) the Apple Watch comes with excessive hype and minimal proof of its accuracy. I’m sure we are going to hear lots of stories about AF being detected by the Watch but we need some published, peer-reviewed data and we need to be very circumspect before embracing it as a reliable AF monitor.
I described in detail in March (see here) my early experience in utilizing AliveCor’s KardiaMobile ECG device in conjunction with their Kardia Pro cloud service to monitor my patient’s with atrial fibrillation (afib). Since that post the majority of my new afib patients have acquired the Kardia device and use it regularly to help us monitor their afib.
This capability has revolutionized my management of atrial fibrillation. In those patients who choose to use AliveCor there is really no need for long-term monitors (Holter monitors, Zio patches, cardiac event monitors) and no need for patients to come to the office to get an ECG when they feel they have gone into afib.
When one of my Kardia Pro patients calls with symptoms or concern of afib, I quickly pull up their chart at Kardiapro.com and review their recordings to determine if they are in or out of rhythm. Most treatment decisions can then be handled over the phone without the need for ordering a monitor or an emergency room or office visit.
One 24 hour period will suffice to show how important KardiaPro is now to my management of my patients with afib
A Day In The Afib Life
Tuesdays I spend the day working in the heart station at my hospital. Typically, on these days I will supervise stress tests, read ECGs and echocardiograms, perform TEES and electrical cardioversions. On a recent Tuesday I had 3 patients scheduled for cardioversion of their atrial fibrillation.
The day before one of these patients called indicating that he suspected he had reverted back to normal rhythm (NSR) based on his Kardia readings. He had had a prior cardioversion after which we know (thanks to daily Kardia recordings) he reverted to afib in 5 days. Subsequently we had started him on flecainide, a drug for maintenance of NSR and scheduled him for the cardioversion.
Not uncommonly after starting flecainide patients will convert to NSR but if they don’t we proceed to an electrical cardioversion.
I logged into KardiaPro and reviewed his dashboard and sure enough his last two ECGs showed sinus rhythm. I congratulated him on this and we canceled his cardioversion for the next day, saving the lab the time and expense of a cancellation the day of the procedure. The patient avoided much stress, time and inconvenience.
It is important to note that in this patient there was no great jump in heart rate with afib compared to NSR. For many patients the rate is much higher with the development of afib and this is often detected by non ECG wearable monitors (like an Apple Watch.) But for patients like this one, an ECG is the only way to know what the rhythm is.
A second patient with afib who had elected not to acquire an AliveCor ECG device showed up for his cardioversion on Tuesday and after evaluating his rhythm it was clear he had spontaneously reverted back to NSR. Prior to my adoption of KardiaPro this was a common and scenario.
The third scheduled cardioversion of the day showed up in afib and we successfully cardioverted him back to NSR. I had not addressed utilizing AliveCor with him. Prior to the procedure he asked me about likely outcomes.
My standard response to this question is that we have a 99.9% success rate in converting patients back to NSR at the time of the cardioversion. However, I can’t predict how long you will stay in NSR after the cardioversion. NSR could last for 5 days or it could last for 5 years. Adding medications like flecainide or amiodarone can significantly reduce the risk of afib recurrence after cardioversion.
At this point he asked me “How do I know if I am in afib?” Whereas many afib patients immediately feel bad and are aware that they have gone out of rhythm, this man like many others was not aware.
Prior to AliveCor my answer would have been to check the pulse daily or look for evidence of high or irregular heart rates on BP monitors or fitness wearables. This scenario provided a wonderful opportunity to test the AliveCor’s accuracy at detecting AF in him. I pulled out my trusty AliveCor mobile ECG and prior to the cardioversion we made the recording below
After the cardioversion we repeated the Alivecor recording and the rhythm (AliveCor’s interpretation) had changed from afib to NSR.
Needless to say, this patient purchased a Kardia device the next day and since the cardioversion he’s made a daily recording which has confirmed NSR. I just logged into Kardia Pro and sure enough he made a recording last night and it showed NSR.
Later in the week I received a call from a patient I had electrically cardioverted a few days earlier. His Kardia device had detected that he had gone back into afib.
I logged into my Mac and saw his KardiaPro chart below.
With perfect precision KardiaPro had verified NSR after the cardioversion lasting for 36 hours. For some reason after dinner the day after the cardioversion, the patient had reverted back to afib. This knowledge greatly facilitates subsequent treatment and eliminates the need for in office ECGs and long term monitors.
Utilization of the Kardia device with the Kardia Pro monitoring service has proved for me to b a remarkable improvement in the management of patients with afib. Managing non Kardia afib patients feels like navigating a forest with a blindfold.
The improvement is so impressive that I find myself exclaiming to my assistant, Jenny, several times a week “How do other cardiologists intelligently care for afibbers without AliveCor?”
I have a few patients who balk at the 15$ per month charge for Kardia Pro and ask why the device and this monthly charge aren’t covered by insurance or Medicare. Given the dramatic reduction that I have noticed in my use of long-term monitors as well as office and ER visits in this population, CMS and third-party insurers would be wise to explore Kardia monitoring as a more cost-effective way of monitoring afib patients.
N.B. I realize this post appears to be an unmitigated enthusiastic endorsement of a commercial product which is quite uncharacteristic for the skeptical cardiologist.
One might wonder if the skepcard is somehow biased or compensated for his endorsement of Kardia.
In all honesty, this sprung from my love of the device’s improvement in my afib management and I have received no payment, monetary or otherwise from AliveCor and I own none of their stock (and I’m not even sure if it is on the stock market.)
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
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 or not they have documented episodes of AF.
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
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,
first episode of AF,
AF precipitated by an acute illness
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.
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.
Six studies showing no difference in outcomes between rhythm and rate control strategies.
1. Wyse DG, Waldo AL, Domanski MJ, Rosenberg Y, Schron E, Kellen J, Greene H, Mickel M, Dalquist J, Corley S. Comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med. 2002; 347: 1825–1833.CrossRefPubMedGoogle Scholar
2. Van Gelder I, Hagens V, Bosker H, Kingma J, Kamp O, Kingma T, Said S, Darmanata J, Timmermans A, Tijssen J, Crijns J. A comparison of rate control and rhythm control in patients with recurrent persistent atrial fibrillation. N Engl J Med. 2002; 347: 1834–1840.CrossRefPubMedGoogle Scholar
3. Carlsson J, Miketic S, Windeler J, Cuneo A, Haun S, Micus S, Walter S, Tebbe U. Randomized trial of rate-control in persistent atrial fibrillation: the Strategies of Treatment of Atrial Fibrillation (STAF) study. J Am Coll Cardiol. 2003; 41: 1690–1696.CrossRefPubMedGoogle Scholar
4.Hohnloser S, Kuick Karl, Lilienthal J. Rhythm or rate control in atrial fibrillation: Pharmacological Intervention in Atrial Fibrillation (PIAF): a randomized trial. Lancet. 2000; 356: 1789–1794.CrossRefPubMedGoogle Scholar
5.Steinberg J, Sadaniantz A, Kron J, Krahn A, Denny D, Daubert J, Campbell B, Havranek E, Murray K, Olshansky B, O’Neill G, Sami M, Schmidt S, Storm R, Zabalgoitia M, Miller J, Chandler M, Nasco E, Greene L. Analysis of cause specific mortality in the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) study. Circulation. 2004; 109: 1973–1980.Abstract/FREE Full TextGoogle Scholar
6.The AFFIRM Investigators. Relationships between sinus rhythm, treatment, and survival in the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) Study. Circulation. 3004; 109: 1509–1513.Google Scholar
In March of 2017 AliveCor introduced Kardia Pro, a cloud-based software platform that allows physicians to monitor patients who use the Kardia mobile ECG device.
I have been utilizing the Kardia mobile ECG device since 2013 with many of my atrial fibrillation (AF) patients and have found it be very useful as a personal intermittent long term cardiac monitor. (see here and here)
I signed up for the Kardia Pro service about 3 months ago and all of my patients who purchased Kardia devices prior to March of 2017 have been migrated automatically to Kardia Pro by AliveCor.
Now (post March 2017), patients who acquire a Kardia device must sign up for the Kardia Pro service at $15 per month to connect with a physician.
I think this is money well spent and I’ll demonstrate how the service works with a few examples.
Monitoring Patients With Atrial Fibrillation
I saw a 68 year old man with persistent atrial fibrillation that was first diagnosed at the time of pneumonia in late 2017.
He underwent a cardioversion after recovering from the pneumonia but quickly reverted back to AF. His prior cardiologist offered him the option of repeat cardioversion and long term flecainide therapy for maintenance of normal sinus rhythm (NSR) but he declined.
When I saw him for the first time in the office a month ago I listened to his heart and to my surprise, noted a regular rhythm: an AliveCor recording in the office confirmed he was in NSR. The patient had been unaware of when he was in or out of rhythm
We discussed methods for monitoring his rhythm at this point which include a 24 Holter monitor, a 7 to 14 day Long Term Monitor, a Cardiac Event Monitor and a Mobile Cardiac Outpatient Telemetry device. These devices are helpful and although expensive are often covered by insurance. They require wearing electrodes or a patch continuously and the results are not immediately available.
I also offered him the option of monitoring his AF using a Kardia device with the recordings connected to me by Kardia Pro.
He purchased the device on his own for $99, downloaded the app for his smartphone and began making recordings.
I enrolled him in my Kardia Pro account and he received an email invitation with a code that he entered which connected his account with mine, allowing me to view all of his recordings as they were made.
When I log into my Kardia Pro account I can now view a graphic display of the recordings he has made with color coding of whether they were considered normal or abnormal by Kardia.
The patient overview page also displays BP information if the patient is utilizing certain Omron devices which work with Kardia.
The display shows that after our office visit he maintained NSR for 3 days (green dots) and then intermittently had ECG recordings classified as AF (yellow dots) or unclassified (black).
The more he used the device and got feedback on when he was in or out of rhythm the more he was able to recognize symptoms that were caused by AF.
I can click on any of the dots and six second strips of the full recording are displayed. In the example below I clicked on 2/27 which has both an unclassified recording (which is atrial flutter) and an AF recording
Clicking on the ECG strips brings up the full 30 second recording on a page that also allows me to assign my formal interpretation. In the example below I added atrial flutter as the diagnosis, changing it from Kardia’s unclassified (Kardia’s algorithm calls anything it cannot clearly identify as AF that is over 100 BPM as unclassified.)
The ECG can then be archived or exported for entry into an EHR.
The benefits of this patient being connected
to me are obvious: we now have an instantaneous patient-controlled method for knowing what his cardiac rhythm is doing whether he is having symptoms or not.
This knowledge allows me to make more informed treatment decisions.
The Kardia Pro Dashboard
When I log into kardia pro I see this screen.
It contains buttons for searching for a specific patient or adding a new patient. Adding new patients is a quick and simple process requiring input of patient demographics including email and birthdate.
From the opening screen you can click on your triage tab. I have elected to have all non normal patient recorded ECGS go into the triage tab.
Another patient’s Kardia Pro page shows that he records an ECG nearly every day and most of the time Kardia documents NSR in the 60s. Overall, he has made 773 recordings and 677 of them were NSR, 28 unanalyzed (due to brevity) , 13 unclassified and 55 showing AF.
Monitoring Rate Control In Patients With AF and Reversion Post-Cardioversion
Another patient I saw for the first time recently has had long-standing persistent AF. His previous cardiologist performed an electrical cardioversion a year ago but the patient reverted back to AF in 40 hours. Before seeing me he had purchased a Kardia mobile ECG device and was using it to monitor his heart rate.
After he accepted my email invitation to connect via Kardia Pro I was able to see his rhythm and rate daily. The Kardia Pro chart belowshows his daily heart rate while in atrial fibrillation. We utilized this to guide titration of his rate controlling medications. Such precise remote monitoring of heart rate in AF (which is often difficult to accurately assess by standard heart rate devices) obviates the need for office visits for 12 lead ECGs or periodic Holter monitors.
I performed a second cardioversion on him after which he made daily recordings documenting maintenance of NSR. With this system we can determine exactly when AF returns, information which will be very helpful in determining future treatment options.
Kardia Pro Plus Kardia Mobile ECG Creates Personal Intermittent Long Term Rhythm Monitor
There are many potential applications of the Kardia ECG device beyond AF monitoring (assessing palpitations, PVCs, tachycardia, etc.) but they are all enhanced when the device is combined with a good cardiologist connected to the device by Kardia Pro.
I’ve gotten spoiled by the information I get from my AF patients who are on Kardia Pro now. When they call the office with palpitations or a sense of being out of rhythm I can determine within a minute what their rhythm is wherever I am (excluding tropical beaches and mountain tops) or wherever the patient is (for the most part.)
On the other hand patients who are not on Kardia Pro have to come into the office for 12-lead ECGs. When they call I feel like my diagnostic tools are limited. Such patients usually end up getting one of the standard Long Term Monitoring (LTM) Devices. If I am fortunate, after a few days to weeks , the results of the LTM will be faxed to my office.
I am optimistic based on this early experience with Kardia Pro that ultimately this service in conjunction with the Kardia Mobile ECG device (or similar products) will replace many of the more expensive and inconvenient long term monitoring devices that cardiologists currently use.
The KardiaBand for Apple Watch from AliveCor has delivered on its unique promise of a medical grade single lead ECG recording made by placing your thumb on your wristwatch band.
The ECG recordings are equivalent in quality to those made by their previously available KardiaMobile (see my prior post here.) After more experience with the Band I think the ease of recording is superior to KardiaMobile and the ability to discriminate atrial fibrillation from normal sinus rhythm is similar to KardiaMobile.
By combining either a KardiaBand or a KardiaMobile device with Kardia’s SmartRhythm monitoring system for Apple Watch we now have the promise of personal monitoring to detect atrial fibrillation.
What is SmartRhythm?
SmartRhythm is AliveCor’s term for its system for monitoring your heart rate and activity levels in order to identify when your rhythm is abnormal.
The system “takes your heart rate and activity data gathered from the Apple Watch and evaluates it using a deep neural network to predict your heart rate pattern.”
The heart rate is obtained from the Apple Watch PPG sensor every 5 seconds. If it differs from what is predicted SmartRhythm notifies you to record an ECG.
If you’d like to learn more detail about the development of SmartRhythm and how it functions, AliveCor has an excellent informational piece here.
You can choose to have the Kardia SmartRhythm display come up whenever your Apple Watch awakens. It’s got information on your heart rate and activity over the preceding several hours
The AliveCor FAQ on SmartRhythm stresses that a notification does not always mean an abnormal rhythm. Clearly false positives can and will occur. The first day I wore my KardiaBand I had several of these.
Causes for false positives include exercise that Apple Watch couldn’t detect, stress or anxiety-in other words, situations where your heart rate is higher than predicted by how much activity you are doing.
The long term record of your SmartRhythm recordings resides on your iPhone . Here’s my record for the last week
Note that Kardia , in addition to tracking your heart rate, also shows you by the green, yellow and orange dots, the times that ECG recordings were made.
Green dots indicate recordings classified as normal and yellow as “unclassified.” In my case most of the unclassified recordings were due to heart rate >100 BPM associated with exercise.
There is one orange dot indicating that Kardia felt the ECG showed “possible atrial fibrillation.”
This happened when I took my Apple Watch off my wrist and put it on one of my patients who has permanent atrial fibrillation. I had him push on the KardiaBand sensor to make an ECG recording and it was correctly identified as atrial fibrillation.
Thus far I have had no notifications of “possible atrial fibrillation” while I have been wearing my watch thus the false positive rate appears acceptably low.
How Does SmartRhythm Perform During Exercise?
I checked out SmartRhythm’s ability to predict normal and abnormal heart patterns by wearing it during a session on my indoor bike trainer. The device did a good job of tracking both my heart rate and activity during the workout. You can view the most recent data by viewing your Apple Watch screen during the workout as below
Or for more detailed information you can view the complete history on your iPhone as below
The system accurately tracked my heart rate and activity (although AliveCor lists stationary bike as an activity that may result in false positives). During a session of weights after the aerobic workout despite erratic heart rates and arm movements it did not notify me of an abnormality. I also did 100 jumping jacks (which involves wildly flailing my arms) and the heart rate remained within the predicted boundaries.
What is more remarkable is that I was able while cycling at peak activity to make a very good quality ECG recording by taking my right hand off the handle bar and pushing my thumb down on the KardiaBand sensor on my left wrist.
This recording clearly displays p waves and is sinus tachycardia. It’s unclassified by Kardia because the rate is >100 BPM.
Afib Patient Experience
One of my patients last week, a 70 year old woman with paroxysmal atrial fibrillation, had already set up SmartRhythm monitoring on her Apple Watch.
I have this patient like many of my afibbers utilizing KardiaMobile to check an ECG when they think they are in afib.
However, she, like many of my afib patients, is totally unaware when her heart is out of rhythm. Such asymptomatic patients are alerted to the fact that they are in afib by detection of a rapid heart rate (from a heart rate tracking wearable or BP monitor) or an irregular heart beat (from BP monitor or by someone checking the pulse) or by a random recording of an ECG.
She’s started using SmartRhythm in the hopes that it will provide a reliable and early warning of when she goes into atrial fibrillation.
We discussed the possibility of stopping the flecainide she takes to maintain normal rhythm to test the accuracy of the SmartRhythm system for detecting atrial fibrillation in her but decided not to. She’s on an oral anticoagulant and therefore protected from stroke so development of atrial fibrillation will not be dangerous for her.
I eagerly await the first real world, real patient reports of SmartRhythm’s performance in atrial fibrillation detection.
If there are any afibbers out there who have had an episode of atrial fibrillation detected by SmartRhythm please let me know the details.
We need such anecdotes along with controlled trials to determine how useful SmartRhythm will be as a personal wearable system for detection of afib.
N.B. I’ve copied a nice section from AliveCor’s website which describes in detail the difference between measuring heart rate from the PPG sensor that all wearable devices use versus measuring the electrical activity of the heart with an ECG.
To understand how Kardia for Apple Watch works, let’s start by talking about your heart, how the Apple Watch and other wearable devices can measure your heart rate, and how an ECG is different from the information you get from a heart rate sensor alone.
Your heart is a pump. With each beat of your heart, blood is pumped through your arteries and causes them to expand. In the time between beats, your arteries relax again. On the underside of the Apple Watch is a sensor, called a photoplethysmogram (PPG), that uses green and infrared LEDs to shine light onto your skin, and detects the small changes in the amount of light reflected back as your arteries expand and relax with each beat of your heart. Using this sensor, the Apple Watch can tell how fast your heart is beating, and how your heart rate changes over time.
But, your heart rate does not tell everything there is to know about your heart. The PPG sensor on the Apple Watch can only see what happens after each heartbeat, as blood is pumped around your body. It can’t tell you anything about what is making your heart beat, or about what happens inside your heart during each beat. An ECG is very different, and tells you a lot more!
An ECG measures the electrical activity in your heart muscles. It detects the small pulse of electricity from the sinoatrial node (the body’s natural pacemaker, which normally initiates each heartbeat) and the large electrical impulses produced as the lower chambers of the heart (the ventricles) contract and relax. By looking at an ECG, a doctor can discern a wealth of information about the health and activity of your heart muscle, much more than you can tell from your heart rate alone. ECGs are the required gold standard for diagnosis of arrhythmias and many cardiac abnormalities, and can even be used to see evidence of acute heart attacks and even events that have occurred in the past.
Research has shown that taking frequent ECGs increases the likelihood of detecting certain arrhythmias, and decreases the mean time to diagnosis.
AliveCor has finally gotten approval from the FDA to release its Kardia Band in the United States.
The skeptical cardiologist is quite excited to get his hands (or wrist) on one and just gave AliveCor $199 to get it.
The device incorporates a mobile ECG sensor into a wrist band that works with either 42 or 38 mm Apple watches. I’ve written extensively about AliveCor’s previous mobile ECG product (here and here) which does a good job of recording a single lead ECG rhythm strip and identifying atrial fibrillation versus normal rhythm,
Hopefully, the Kardia Band will work as well as the earlier device in accurately detecting atrial fibrillation.
According to this brief video to make a recording you tap the watch screen then put your thumb on the sensor on the band.
The app can monitor your heart rate constantly and alerts you to make a recording if it thinks you have an abnormal rhythm.
I was alerted to the release of Kardia by Larry Husten’s excellent Cardio Brief blog and in his post he indicates that the alert service , termed Smart Rhythm, requires a subscription of $99 per year.:
AliveCor simultaneously announced the introduction of SmartRhythm, a program for the Apple Watch that monitors the watch’s heart rate and activity sensors and provides real-time alerts to users to capture an ECG with the Kardia Band. The program, according to an AliveCor spokesperson, “leverages sophisticated artificial intelligence to detect when a user’s heart rate and physical activity are out of sync, and prompts users to take an EKG in case it’s signaling possible abnormalities like AFib.”
The Kardia Band will sell for $199. This includes the ability to record unlimited ECGs and to email the readings to anyone. The SmartRhythm program will be part of the company’s KardiaGuard membership, which costs $99 a year. KardiaGuard stores ECG recordings in the cloud and provides monthly summary reports on ECGs and other readings taken.
AliveCor tells me my Kardia Band will be shipped in 1-2 days and I hope to be able to give my evaluation of it before Christmas.
Please note that I paid for the device myself in order to avoid any bias that could be introduced by receiving largesse from AliveCor.
N.B. Larry Husten’s article includes some perspective and warnings from two cardiologist and can be read here.
Another article on the Kardia Band release suggests that the Smart Rhythm program at $99/ year is a requirement.
Perhaps, AliveCor’s David Albert can weigh in on whether the annual subscription is a requirement for making recordings or just allows the continuous monitoring aspect.
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.”
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.
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.”
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.
The Skeptical Cardiologist is a strong proponent of empowering patients with atrial fibrillation by utilizing personal cardiac rhythm devices such as Afib Alert or AliveCor’s Kardia.
I’ve written about my experiences with the initial versions of the Kardia mobile ECG device and the service it provides here and here.
I have been monitoring dozens of my afib patients using AliveCor’s Physician Dashboard.
Recently AliveCor changed fundamentally the way their app works such that for new users much of the functionality I described in my previous posts now requires subscribing to their Premium service which costs $9.99 per month or $99 per year.
What Has Changed With The Kardia App
The Kardia device which works with both iOs and Android smart
phones is unchanged and still generates a “medical-grade” single lead rhythm strips which appears within the Kardia app.
The app still is reasonably accurate at identifying atrial fibrillation or normal heart rhythms and offers a fee-based service for interpretation of unclassified ECGs.
However, for new purchasers of Kardia, the capability to access, email or print prior ECG recordings has gone away. Prior to March of this year, Kardia users could access prior ECG tracings which were stored in the cloud by touching the “Journal” button on the app. These older tracings could be emailed and they were available through the cloud for a physician like myself to review at any time.
Now new Kardia purchasers will find that when they make an ECG recording they have the option to email a PDF of the ECG but once they hit the DONE button it is gone and is not stored anywhere.
For my patients purchasing after March, 2017 this means that unless they purchase Kardia Premium service I will not be able to view their ECG recordings online.
An AliveCor account executive summarized for me the changes as follows:
We added a significant number of features over the past year and a half, and grandfathered all users on March 16th, 2017. New users now have the option to download and use Kardia for free, but the premium services are $9.99/mo or $99/year. Kardia Premium allows unlimited storage and history of their EKGs, summary reports with longitudinal data, blood pressure monitoring and tracking weight and medication.
Why Journal Functionality Is Important
If you purchased your AliveCor/Kardia device prior to March 16th, 2017 ago the journal functionality still works. Let’s call such customers “Journal Grandfathered”.
This Journal functionality is important in a number of ways:
My Journal Grandfathered patients can bring their phones with them during an office visit and we can review all of their ECG tracings.
Journal gGandfathered Kardia users can email their old tracings to their physicians or to anyone they wish (even the skeptical cardiologist!). They can also print them out and save PDFs of the tracings.
I can view through my online physician account all of my Journal Grandfathered patients. This means any time a patient of mine makes a recording that is unclassified or suggests atrial fibrillation I can be notified and immediately view it online.
This fundamental change took place as AliveCor attempts to convince purchasers of the Kardia device to use their Premium service.
Why AliveCor Changed The Kardia App Function
Dr. David Albert, inventor and cardiologist and the founder of AliveCor was kind enough to talk with me about this change.
He indicates that of the 150,000 AliveCor users, 10,000 are now using the Kardia Premium service. About 20% of new users elect Kardia Premium.
Prior to the change all AliveCor users had their old ECG recordings stored in the cloud in a HIPPA compliant fashion. This free service was costing AliveCor quite a bit and the company felt it was best to switch to a subscription service to provide this secure cloud storage.
With the change to the (relatively inexpensive) subscription service, patients will get additional features. As the AliveCor account executive described:
Kardia Premium allows unlimited storage and history of their EKGs, summary reports with longitudinal data, blood pressure monitoring and tracking weight and medication.
I’ve looked at the Premium service and it seems quite useful when combined with a connected physician utilizing Kardia Pro. I’ll evaluate the Premium service and the physician Kardia Pro service further and write a full post on its features in the near future.
If you are not grandfathered and want to stick with the Basic Kardia service you still have an immensely useful and inexpensive device which allows personal detection of your cardiac rhythm. Just remember to email yourself the ECG recording you just made before you hit DONE.