The skeptical cardiologist still feels that KardiaPro has eliminated use of long term monitoring devices for most of his afib patients
However not all my afib patients are willing and able to self-monitor their atrial fibrillation using the Alivecor Mobile ECG device. For the Kardia unwilling and many patients who don’t have afib we are still utilizing lots of long term monitors.
The ambulatory ECG monitoring world is very confusing and ever-changing but I recently came across a nice review of the area in the Cleveland Clinic Journal of Medicine which can be read in its entirety for free here.
This Table summarizes the various options available. I particularly like that they included relative cost. .
The traditional ambulatory ECG device is the “Holter” monitor which is named after its inventor and is relatively inexpensive and worn for 24 to 48 hours.
The variety of available devices are depicted in this nice graphic:
For the last few years we have predominantly been using the two week “patch” type devices in most of our patients who warrant a long term monitor. The Zio is the prototype for this but we are also using the BioTelemetry patch increasingly.
The more expensive mobile cardiac outpatient telemetry (MCOT) devices like the one below from BioTel look a lot like the patches now. The major difference to the patient is that the monitor has to be taken out and recharged every 5 days. In addition, as BioTel techs are reviewing the signal from the device they can notify the patient if the ECG from the patch is inadequate and have them switch to an included lanyard/electrode set-up.
The advantage of the patch monitors is that they are ultraportable, relatively unobtrusive and they monitor continuously with full disclosure.
The patch is applied to the left chest and usually stays there for two weeks (and yes, patients do get to shower during that time) at which time it is mailed back to the company for analysis.
The skeptical cardiologist was quite enthusiastic about AliveCor’s Kardia Band for Apple Watch upon its release late in 2017.
I was able to easily make high fidelity, medical grade ECG recordings with it and its AI algorithm was highly accurate at identifying atrial fibrillation (see here). This accuracy was subsequently confirmed by research.
Many skepcard readers spent $200 dollars for the Kardia Band and had found it to be very helpful in the management of their atrial fibrillation.
However, in December of 2018 Apple added ECG recording to its Apple Watch 4, essentially building into the AW4 the features that Kardia Band had offered as an add on to earlier Apple Watch versions.
In my evaluation of the Apple Watch I found it to be “an amazingly easy, convenient and straightforward method for recording a single channel ECG” but its algorithm in comparison to AliveCor’s yielded more uncertain diagnoses.
Given it size, prominence and vast resources, Apple’s very publicized move into this area seemed likely to threaten the viability of AliveCor’s Kardia Band.
But then-interim CEO (and current COO) Ira Bahr later told MobiHealthNews that his company’s broader business wasn’t threatened by its new direct competitor.
“We’re not convinced that Apple’s excellent, engaging product is a competitor yet,” he said in February. “We believe that from a price perspective, this product is least accessible to the people who need it most. If you’re not an Apple user, you’ve got to buy an Apple Watch, you’ve got to buy an iPhone to make the system work. So their technology is excellent, but we think the platform is both complicated and expensive and certainly not, from a marketing perspective, targeting the patient populations we target.”
Indeed, AliveCor’s Mobile ECG device and its recently released 6 lead ECG are doing very well but the threat to the viability of KardiaBand was real and MobiHealth News announced Aug. 19 that AliveCor had officially ended sales of the Kardia Band.
An AliveCor representative told MobiHealthNews that the company “plans to continue supporting KardiaBand indefinitely” for those who have already purchased the device. The company’s decision was first highlighted by former MobiHealthNews Editor Brian Dolan in an Exits and Outcomes report.
Mr. Bahr has confirmed to me that AliveCor does plan to continue supporting KardiaBand indefinitely. This includes replacement of KardiaBand parts.
Did Apple Kill Smart Rhythm?
The informed reader who notified me of AliveCor’s decision also notes:
The official reason is that they could not keep up with the Apple Watch updates and therefore the Smart Rhythm feature did not work properly.
I think many of us knew from the beginning that smart rhythm was not very accurate But in spite of that the Kardia band provided a valuable convenience over their other products.
It does appear that Smart Rhythm is no more.
AliveCor’s website was updated 6 days ago to state that Smart Rhythm was discontinued:
” due to changes beyond our control in the Apple Watch operating system, which caused SmartRhythm to perform below our quality standards”
Likely, as my reader was told, the frequent AW4 updates plus the lack of a large KardiaBand user base made it unprofitable for AliveCor to continue to support Smart Rhythm.
Smart Rhythm, of course was AliveCor’s method for watch-based detection of atrial fibrillation. It clearly had limitations, including false positives but given AliveCor’s track record of dedication to high quality and accuracy I assumed it would improve over time..
Apple, on December 6, 2018 with the release of its watchOS 5.1.2 for AW4 announced its own version of Smart Rhythm at the same time it activated the ECG capability of AW4.
Apple called this feature “the irregular rhythm notification feature” and cited support for its accuracy from the widely ballyhooed Apple Heart Study (which I critiqued here.)
The irregular rhythm notification feature (TIRNF)was recently studied in the Apple Heart Study. With over 400,000 participants, the Apple Heart Study was the largest screening study on atrial fibrillation ever conducted, also making it one of the largest cardiovascular trials to date. A subset of the data from the Apple Heart Study was submitted to the FDA to support clearance of the irregular rhythm notification feature. In that sub-study, of the participants that received an irregular rhythm notification on their Apple Watch while simultaneously wearing an ECG patch, 80 percent showed AFib on the ECG patch and 98 percent showed AFib or other clinically relevant arrhythmias.
Despite widely publicized reports of lives being saved by TIRNF we still don’t know whether its benefits outweigh its harms. It is not clear what its sensitivity is for detecting atrial fibrillation and I have reported one patient who was in atrial fibrillation for 3 hours without her AW4 alerting her to its presence.
For AW4 users, absence of an alert should not provide reassurance that your rhythm is normal.
Thus is does appear that the Goliath Apple hath smote the David AliveCor in the watch-based afib battle. This does not bode well for consumers and patients as I think as competition in this area would make for better products and more accountability.
Per AliveCor the KardiaBand currently works with all all Apple Watches except the original one.
The Apple TIRNF per Apple:
is available for Apple Watch Series 1 and later and requires iPhone 5s or later on iOS 12.1.1 in the US, Puerto Rico, Guam and US Virgin Islands. The irregular rhythm notification feature does not detect a heart attack, blood clots, a stroke or other heart-related conditions including high blood pressure, congestive heart failure, high cholesterol or other forms of arrhythmia.
Old habits die hard in medicine. For decades the skeptical cardiologist and his cardiology brethren and sistren have prescribed aspirin to prevent stroke in patients with atrial fibrillation.
For those patients with atrial fibrillation (AF) who were considered low risk it was felt that aspirin provided some benefit in preventing the clots that fly out of the heart (and land in arteries elsewhere in the body) at an acceptably low risk of bleeding. For higher risk patients more powerful and effective agents (oral anticoagulants) are usually recommended.
The American guidelines on AF (2014) gave a IIB recommendation to aspirin. IIB is not a ringing endorsement having been described as “this is our suggestion, but you may want to think about it.”
For patients with nonvalvular AF and a CHA2DS2-VASc score of 1, no antithrombotic therapy or treatment with an oral anticoagulant (OAC) or aspirin may be considered. (Level of Evidence: C)*
Thus, in the 2016 European guidelines on the management of AF the authors state that “the evidence supporting antiplatelet mono therapy (e.g. aspirin or clopidogrel) for stroke prevention in AF is very limited” and the bleeding rate” is similar to OAC”:
Aspirin and other antiplatelets have no role in stroke prevention (III A). The combination of anticoagulation with antiplatelets increases bleeding risk and is only justified in selected patients for a short period of time; for example, in patients with an acute coronary syndrome or stent, balancing the risk of bleeding, stroke and myocardial ischaemia (IIa B/C).
Stroke risk evaluation is based on the CHADS-VASc score. With a score ≥2 in male and ≥3 in female patients, anticoagulation for stroke prevention is clearly recommended, while in a score of 1 in males and 2 in females, anticoagulation should be considered. No antithrombotic therapy of any kind should be prescribed in patients with a CHADS-VASc score of 0 (males) or 1 (females).
Antiplatelet therapy increases bleeding risk, especially dual antiplatelet therapy (2.0% vs. 1.3% with antiplatelet monotherapy; P < 0.001), with bleeding rates that are similar to those on OAC. Thus, antiplatelet therapy cannot be recommended for stroke prevention in AF patients.
“The European guidelines have done away with aspirin for stroke prevention in atrial fibrillation. It barely made it into our current US guidelines. I don’t think aspirin should be in there and I don’t think it will be there in the next guidelines. The role of aspirin will fall away,” said Bernard J. Gersh, MB, ChB, DPhil, Professor of Medicine at the Mayo Clinic in Rochester, Minnesota. “It’s not that aspirin is less effective than the oral anticoagulants, it’s that there’s no role for it. There are no good data to support aspirin in the prevention of stroke in atrial fibrillation.”
“The use of aspirin has probably been misguided, based upon a single trial which showed a profound effect and was probably just an anomaly,” said N.A. Mark Estes III, MD, Professor of Medicine and Director of the New England Cardiac Arrhythmia Center at Tufts University in Boston, and a past president of the Heart Rhythm Society
I would just take it off of your clinical armamentarium because the best available data indicate that it doesn’t prevent strokes. I’m certainly not using it in my patients. Increasingly in my patients with a CHA2DS2-VASc of 1, I’m discussing the risks and benefits of a novel oral anticoagulant,” said Dr. Estes.
Those are amazingly definitive statements. But, as I’ve learned we can’t just except what the “experts” and the guidelines tell us we have to look at the original studies informing these decisions.
It compared warfarin (measured by PT ratio) to placebo and aspirin 325 mg to placebo in preventing stroke in AF patients. Warfarin reduced stroke by 67% and aspirin by 42%. The risk of significant bleeding was similar at around 1.5% per year for all three arms.
Based on this and other AF trials (AFASAK, CAFA, SPINAF, EAFT, et al. ) when I gave talks or taught cardiology fellows in the 1990s my message (similar to this presentation) emphasized the superior benefits of warfarin compared to aspirin (especially when monitored by INR in a 2.0 to 3.0 range) in higher risk AF patients. Overall it was felt that aspirin (dosing varying from 100 to 325 mg) reduced stroke/embolism by 20-30% compared to placebo and would offer benefit to those patients at low risk or who could not tolerate warfarin.
Based on the 2014 American guidelines (and a focused update in 2019 which did not address this issue) I had not been actively taking my low risk patients off baby aspirin.
I was prompted to re-research this question and write this post because a 58 year old woman with paroxysmal AF and hypertension called the office today asking if I wanted her to take a baby aspirin daily. She has a CHADS2VASC score of 2 (woman and hypertension) and falls into the category where we should have an in depth conversation about the risks and benefits of anticoagulant therapy.
I have that discussion with her each visit and thus far we’ve decided to hold off on starting an anticoagulant drug like Eliquis. She has promised to record her ECG daily (using her Kardia Mobile ECG device) and report any onset of AF. If AF recurs we will have another discussion about Eliquis.
I spent several hours pouring over the original studies and more recent studies, reviews and meta-analyses and reached the following conclusions:
With the advent of the newer oral anticoagulants (NOACs) in the last decade which offer better stroke reduction and less bleeding than warfarin patient-physician discussions should be about taking a NOAC or not. Aspirin should not be considered as a lower risk/effective alternative as its benefits are minimal and bleeding risks similar to NOACs.
I told my patient no on the daily baby aspirin and from now on I will recommend stopping aspirin (assuming no other reason to be on it) to all my low risk AF patients.
The components of the stroke risk score- CHA2DS2-VASc = Congestive Heart failure, hypertension, Age ≥75 (doubled), Diabetes, Stroke (doubled), Vascular disease, Age 65–74, and Sex (female);
For those interested in a discussion on why females get a point in the risk score but a different cut-off for OAC therapy this is from the ESC guidelines:
Many risk factors contribute to the increased risk of stroke in patients with AF as expressed in the CHA2DS2-VASc score. The evidence for female sex as a risk factor has been assessed in many studies. Most studies support the finding that females with AF are at increased risk of stroke. One meta-analysis found a 1.31-fold (95% CI: 1.18–1.46) elevated risk of stroke in females with AF, with the risk appearing greatest for females ≥75 years of age (S4.1.1-35). Recent studies have suggested that female sex, in the absence of other AF risk factors (CHA2DS2-VASc score of 0 in males and 1 in females), carries a low stroke risk that is similar to males. The excess risk for females was especially evident among those with ≥2 non–sex-related stroke risk factors; thus, female sex is a risk modifier and is age dependent (S4.1.1-49). Adding female sex to the CHA2DS2-VASc score matters for age >65 years or ≥2 non–sex-related stroke risk factors
If you’re curious what constitutes a IIB recommendation it is described in the yellow box below My best summary is still “not a ringing endorsement”.
If you want to see the ESC guideline recommendations in detail
In less than a month AliveCor plans to release its KardiaMobile 6L which will provide 6 ECG leads using a smartphone based mobile ECG system that is similar to the Kardia single lead system.
AliveCor’s website proclaims “This is your heart x 6.”
I was fortunate enough to obtain a demo version of the 6L and have been evaluating it.
My first impressions are that this is a remarkable step forward in the technology of personal ECG monitoring. I’m not sure if I would call it “your heart x 6” but I feel the ability to view six high quality leads compared to one is definitely going to add to the diagnostic capabilities of the Kardia device.
Kardia 6L Setup And Hardware
The 6L is similar in design and function to the single lead device.
I’m including this cool spinning video (from the AliveCor website) which makes it appear, slick, stylish and futuristic
Once paired to the Kardia smartphone app (available for iOS or Android smartphones for free) it communicates with the smartphone using BLE to create ECG tracings.
Like the single lead Kardia the 6L has two sensors on top for left and right hand contact. But in addition, there is a third on the bottom which can be put on a left knee or ankle.
The combination of these sensors and contact points yield the 6 classic frontal leads of a full 12 lead ECG: leads I, II, III, aVL, aVR, and aVF. This is accomplished, AliveCor points out “without messy gels and wires.
I found that using the device was simple and strait-forward and we were able to get high quality tracings with minimal difficulty within a minute of starting the process in all the patients we tried it on.
The Diagnostic Power Of Six Leads
Below is a tracing on a patient with known atrial fibrillation. The algorithm correctly diagnoses it. With 6 different views of the electrical activity of the atrium I (and the Kardia algorithm) have a better chance of determining if p waves are present, thereby presumably increasing the accuracy of rhythm determination
Depending on the electrical vector of the left and right atria, the best lead to visualize p waves varies from patient to patient, thus having 6 to choose from should improve our ability to differentiate sinus rhythm from afib.
In the example below, the Kardia 6L very accurately registered the left axis deviation and left anterior fascicular block that we also noted on this patient’s 12 lead ECG. This 6L capability, determining the axis of the heart in the frontal plane, will further add to the useful information Kardia provides.
For a good summary of axis determination and what abnormal axes tells us see here.
The History of ECG Leads
When I began my cardiology training the 12-lead ECG was standard but it has not always been that way. I took this timeline figure from a nice review of the history of the ECG
Einthoven’s first 3 lead EKG in 1901 was enormous.
It is mind-boggling to consider that we can now record 6 ECG leads with a smartphone and a device the size of a stick of gum
For the first 30 years of the ECG era cardiologists only had 3 ECG leads to provide information on cardiac pathology. Here’s a figure from a state of the art paper in 1924 on “coronary thrombosis” (which we now term a myocardial infarction) showing changes diagnostic of an “attack” and subsequent atrial fibrillation
In the 1930s the 6 precordial leads were developed providing more information on electrical activity in the horizontal axis of the heart. The development of the augmented leads (aVr, aVL, aVF) in 1942 filled in the gaps of the frontal plane and the combination of all of these 12 leads was sanctified by the AHA in 1954.
I’ll write a more detailed analysis of the Kardia 6L after spending more time using it in patient care.
Specifically I’ll be analyzing (and looking for published data relative to):
-the relative accuracy of the 6L versus the single lead Kardia for afib determination (which, at this point would be the major reason for current Kardia users to upgrade.)
-the utility of the 6L for determination of cardiac axis and electrical intervals in comparison to the standard 12 lead ECG, especially in patients on anti-arrhythmic drugs
For now, this latest output from the meticulous and thoughtful folks at AliveCor has knocked my socks off!
N.B. If one uses the single lead kardia device in the traditional manner (left hand and right hand on the sensors) one is recording ECG lead I. However, if you put your right hand on the right sensor and touch the left sensor to your left leg you are now recording ECG lead II and if to the right leg, ECG lead III.
I describe this in detail here. For certain individuals the lead II recordings are much better than lead I and reduce the prevalence of “unclassified” recordings.
My feeling is that by automatically including the leg (and leads II and III) the 6L will intrinsically provide high voltage leads for review and analysis, thereby improving the ability to accurately classify rhythm.
And (totally unrelated to the 6L discussion) one can also record precordial ECG leads by putting the device on the chest thus theoretically completing the full 12 leads of the standard ECG.
Please also note that I have no financial or consulting ties to AliveCor. I’m just a big fan of their products.
The wide-spread public conception that catheter ablation cures atrial fibrillation and reduces one’s risk of stroke or dying has fueled a $4.5 billion industry. Until very recently there were no published randomized trials supporting this expensive and risky procedure.
The recently published landmark CABANA trial found that in patients with afib “the strategy of catheter ablation, compared with medical therapy, did not significantly reduce the primary composite end point of death, disabling stroke, serious bleeding, or cardiac arrest. ”
So there is no proven benefit of ablation on death, stroke, bleeding or cardiac arrest. This means that a medical management approach to management of afib is always an acceptable approach. Especially an enlightened medical approach.
In CABANA, women and those patients >75 years of age did worse with ablation as this chart shows.
What about complications? I mentioned that ablation was risky and this is because any time you put a catheter in someone’s heart you can create life-threatening problems. When you then heat up the tip of that catheter it is possible to burn/damage/destroy things that are not your target.
A reassuring finding of CABANA was that ablation did not do worse than drugs. But one of the messages I heard from HRS was that CABANA showed that AF ablation is safe. This is a problem.
The complications in the ablation arm were more serious and more numerous than those in the drug arm. We will have to wait for the published paper for formal comparisons. CABANA likely represents a best-case scenario because it allowed only experienced operators and centers to be part of the trial. Many people undergo ablation by less experienced operators.
Another important safety issue is the asymmetry of procedural complications. When you talk privately with ablation doctors, many, perhaps most, relay the story of a tragic death of an otherwise healthy middle-aged adult from an atrial-esophageal fistula.
Yes. A well-recognized and highly feared complication of ablation , atrial-esophageal fistula, causes rapid death due to exsanguination through a channel between the left atrium and the esophagus which develop due to destruction/burning of the normal esophageal/atrial tissue.
In this chart taken from the CABANA abstract presentation you can see the complications which do not include a highly feared atrial-esophageal fistula.
Can Catheter Ablation Improve Quality of Life?
Basically, after the CABANA trial we have no evidence that ablation will improve hard outcomes in afib patients. However, there are numerous patients who feel they have greatly benefited from the procedure, experiencing years of afib free existence.
This benefit of ablation, of improving quality of life and making patients feel better is important.
The CABANA trial also looked at quality of life and in part II of this article I’ll examine that in detail.
Update 6/12/2019 357 PM.
Twitter follower @mrice5025 was kind of enough to read the above closely enough to realize that the number of atrial esophageal fistulae was actually zero in the CABANA trial and I have corrected the text accordingly.
I have seen a case of this mostly fatal complication in a patient who had an ablation done at an outside hospital 5 weeks earlier and who rapidly died from it and I try to be very aware of its possibility as early diagnosis and surgery is the key to survival.
AF ablation carries a small risk of complications with the most serious being atrioesophageal fistula (AEF). Although the incidence is less than 0.1%, it is usually fatal Esophageal perforation or fistula was reported in 31 patients (0.016%) in the Global Survey of Esophageal and Gastric Injury in Atrial Fibrillation study. Symptom onset for esophageal perforation or fistula was reported on average 19.3 days after the ablation procedure but could appear as short as 6 days and as long as 59 days post ablation.Esophageal injury has been observed most frequently with percutaneous radiofrequency ablation, although it has also been reported with other energy sources including cryoablation,high-intensity focused ultrasound and even surgical ablation.
The featured image comes from this Cleveland Clinic video which has some great graphics and reasonable information (once you get by the annoying lady at the beginning who describes ablation as “an excellent minimally invasive” procedure.)
At my hospital, St. Luke’s, I have three outstanding electrophysiologists who do excellent ablations,, Jonas Cooper, Cary Fredman, and Mauricio Sanchez.
The skeptical cardiologist is a firm believer in the benefit of maintaining normal rhythm in most patients who develop atrial fibrillation (AF, see here.)
Sometimes this can be accomplished by lifestyle changes (losing pounds and cutting back on alcohol , treating sleep apnea, etc.) but more often successful long term maintenance of normal rhythm (NSR) requires a judicious combination of medications and electrical cardioversions (ECV).
It is also greatly facilitated by a compliant and knowledgeable patient who is regularly self-monitoring with a personal ECG device.
My article on electrical cardioversion (see here) was inspired by a patient (we’ll call her Sandy) who asked me in April of 2016, “how many times can you shock the heart?”
In 2016 I performed her fifth cardioversion and last week I did her sixth.
Her story of AF is a common one which exemplifies how excellent medical management of AF can cure heart failure and mitral regurgitation and create decades of AF-free, happy and healthy existence.
A Tale Of Six Cardioversions
Sandy had her first episode of atrial fibrillation in 2001 and underwent a cardioversion at that time and as far as she knew had no AF problems for 14 years. I’ve seen numerous cases like this where following a cardioversion, patients maintain NSR for a long time without medications but I’ve also seen many in whom AF came back in days to months.
In 2015 she saw her PCP for routine follow-up and AF with a rapid rate was detected. She had been noticing shortness of breath on exertion and a cough at night but otherwise had no clue she was out of rhythm.
When I saw her in consultation she was in heart failure and her echocardiogram demonstrated a left ventricular ejection fraction of 50% with severe mitral regurgitation. She quickly went back into AF after an electrical cardioverson (ECV) and reverted to AF again following a repeat ECV after four days on amiodarone.
Since amiodarone can take months to reach effective levels in the heart we tried one more time to cardiovert after loading on higher dosage amiodarone for one month. This time she stayed in NSR
Following that cardioversion she has done extremely well. Her shortness of breath resolved and follow up echocardiograms have demonstrated resolution of her mitral regurgitation.
She had purchased a Kardia mobile ECG device for personal monitoring of her rhythm and we were able to monitor her rhythm using the KardiaPro dashboard. Recordings showed she was consistently maintaining NSR after her 2016 ECV
I’ve written extensively on the great value of KardiaPro used in conjunction with the Kardia mobile ECG device for monitoring patients pre and post cardioversion for atrial fibrillation. Sandy does a great job of making frequent Kardia ECG recordings, almost on a daily basis so even though she has no symptoms we are alerted to any AF within 24 hours of it happening.
Amiodarone-The Big Medical Gun For Stopping Atrial Fibrillation
The recurrence of AF Sandy had in 2016 occurred 8 months after I had lowered her amiodarone dosage to 100 mg daily.
Amiodarone is a unique drug in the AF toolkit.
It is the by far the most effective drug for maintaining sinus rhythm, an effect that makes it our most useful antiarrhythmic drug (AAD).
It is cheap and well-tolerated.
Uniquely among drugs that we use for controlling atrial fibrillation it takes a long time to build up in heart tissue and a long time to wear off.
It is the safest antiarrhythmic drug from a cardiac standpoint. Unlike many of the other AADs we don’t have to worry about pro-arrhythmia (bringing out more dangerous rhythms such as ventricular tachycardia or ventricular fibrillation) with amio.
Amiodarone, however, is not for all patients-it has significant long term side effects that necessitate constant vigilance by prescribing physicians including thyroid, liver and lung toxicity.
I monitor my patients on amiodarone with thyroid and liver blood tests every 4 months and a chest x-ray yearly and I try to utilize the minimal dosage that will keep them out of AF.
In Sandy’s case it was apparent that 100 mg was too little but with an increase back to 200 mg daily, the AF remained at bay.
In early 2017, Sandy read on Facebook that amio was a “poison” and after discussing risks and benefits we decided to lower the dosage to 200 mg alternating with 100 mg. It is common and appropriate for patients to be fearful of the potential long term and serious consequences of medications. For any patient taking amiodarone I always offer the option of stopping the drug with the understanding that there is a strong likelihood of recurrent AF within 3 months once the drug wears off.
In October, 2018 with Sandy continuing to show normal heart function and maintain SR as documented by her daily Kardia ECG tracings we decided to further lower the dosage to 100 mg daily.
Six months later she noted one day that her Kardia reading was showing a heart rate of 159 bpm and diagnosing atrial fibrillation. AF had recurred on the lower dosage of amiodarone. She had no symptoms but based on prior experience we knew that soon she would go into heart failure.
Thus, her amiodarone was increased and a sixth cardioversion was performed. We could find no trigger for this episode (unless the bloody mary she consumed at a Mother’s Day Brunch 2 days prior was the culprit.)
Medical Management With Antiarrhythmics Versus Ablation
Many patients seek a “cure” for atrial fibrillation. They hear from friends and neighbors or the interweb of ablation or surgical procedures that promise this. Stopafib.org, for example, promotes these types of procedures saying “Catheter ablation and surgical maze procedures cure atrial fibrillation”
In my experience the majority of patients receiving ablation or surgical procedures (Maze procedure and its variants) ultimately end up having recurrent episodes of atrial fibrillation. Guidelines do not suggest that anticoagulants can be stopped in such patients. Often, they end up on AADs.
I’ve prepared a whole post on ablation for AF but the bottom line is that there is no evidence that ablation lowers the AF patient’s risk of dying, stroke, or bleeding. My post will dig deeper into the risks and benefits of ablation.
There is no cure for AF, surgical, catheter-based or medical.
In the right hands most patients can do very well with medical management combined with occasional cardioversion.
Who posseses the right hands?
In my opinion, most AF patients are best served by a cardiologist who has a special interest in atrial fibrillation and takes the time to read extensively and keep up with the latest developments and guideline recommendations in the area. This does not need to a be an electrophysiologist (EP doctor-one who specializes in the electrical abnormalities of the heart and performs ablations, pacemakers and defibrillators.)
I have a ton of respect for the EP doctors I work with and send patients to but I think that when it comes to doing invasive, risky procedures the decision should be based on a referral/recommendation from a cardiologist who is not doing the procedure.
In many areas of cardiology we are moving toward an interdisciplinary team of diagnosticians, interventionalists, surgeons and non-cardiac specialists to make decisions on performance of high-risk and high-cost but high-benefit procedures like valve repair and replacement, closure of PFOs and implantation of left atrial appendage closure devices.
It makes sense that decisions to perform high-risk , high-cost atrial fibrillation procedures also be determined by a multi-disciplinary team with members who don’t do the procedure.
This is a rule of thumb that can also be applied to many surgical procedures as well. For example, the decision to proceed to surgical treatment of carotid artery blockages (carotid endarterectomy) is typically made by the vascular surgeons who perform the procedure. In my opinion this decision should be made by a neurologist with expertise in neurovascular disease combined with a good cardiologist who has kept up with the latest studies on the risks and benefits of carotid surgery and is fully briefed on the latest guideline recommendations.
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.)