I’ve been evaluating the ability of a mobile hand-held ECG device called AfibAlert to detect atrial fibrillation for the last few weeks.
I found that the device made very reliable and consistent recordings of cardiac rhythm and did a reasonably good job of detecting atrial fibrillation (afib).
The device came in a plastic case with a USB cable for uploading recordings and two metal bracelets which attach to electrodes and provide an alternative recording method.
The device itself is about 6 by 3 by 1 inch.
Recordings are made by placing your thumbs on the silver/siver chloride electrodes
After a few seconds the display in the center will give heart rate and after 45 seconds the
device will make a decision about your rhythm:
If it diagnoses normal sinus rhythm a green check appears and if it diagnoses afib a red telephone appears.
If it is confused you get yellow circular arrows.
As the maker of the device explains:
Lohman Technologies’ patented algorithm analyzes the patient’s heartbeat and the appropriate icon illuminates to show what action is needed. AfibAlert’s® algorithm was validated against 51,000+ ECG strips from the MIT-BIH Atrial Fibrillation Database with known diagnosis. The Afib monitor’s results were excellent, with 94.6% accuracy in detecting the presence of arrhythmias. Each recording produces a 45-second diagnostic quality ECG rhythm strip
The device I tested does not allow you to immediately see the ECG tracing. The recordings are uploaded to a PC via USB cable and then can be viewed as a PDF document.
I made 17 recordings on patients in my office one day. The age range was 50 to 93 years and most patients were able to rapidly and easily grasp the device with thumbs appropriately positioned to make interpretable recordings.
Only 2/17 came back. yellow. In both cases, I repeated the recording and the device was able to make the correct diagnosis. Twice I got the yellow signal on an elderly, partially blind patient who had trouble keeping his thumb on the electrode.
In 15 cases of normal sinus rhythm the device correctly identified NSR.
In one case of atrial fibrillation the device correctly identified atrial fibrillation.
In one case of SR with
APCs the device
incorrectly identified afib
Overall the device correctly classified 88% of the tracings. This was superior to the device I normally utilize ( AliveCor/Kardia mobile ECG) in head to head comparison (I’ll present this comparison in a subsequent post).
My bullet points on the AfibAlert device:
-5 stars for Ease of Recording
-5 stars for Quality of recording
In all cases that uploaded, the recordings were very clear and free of artifact. The device did not upload yellow signal events and I presume more artifact is present in these recordings.
-2 stars for Convenience.
I found the software and uploading to be very awkward and slow. The company indicates new software soon to be released along with the ability to interface directly with iPads or smartphones that hopefully will improve this factor.
The inability to instantaneously view the ECG tracings means I cannot use it in my office to screen patients for arrhythmias. However, if a patient is solely using it to determine if afib is present or absent, this information is available right away.
-3 stars for Accuracy.
It does a reasonable job of identifying the patient who is in normal rhythm versus one in atrial fibrillation.
However, like AliveCor and other devices which strictly look at the variability of the pulse, it can be easily fooled by premature beats, especially when they are frequent, and inappropriately classify these as afib resulting in false positives.
In addition, when afib rates are very slow and thus much less variable it is likely AfibAlert will incorrectly classify them as normal thus resulting in false negatives.
False Negatives and False Positives
False negatives result in delayed diagnosis of afib. Patients will be falsely reassured that their rhythm is normal when it is not.
False positives result in needless anxiety and testing/treatment.
If afib monitoring devices are to be successful they have to have a very low frequency of both types of inaccuracy.
The solution to inaccuracy of interpretation, of course, is to have a cardiologist over-read the tracings.
AfibAlert recordings are available online for review by your personal physician after being uploaded. This requires your physician to have an account with AfibAlert. There is no capability for having the recordings over read by an online cardiologist for a charge.
As far as I can tell the device is only available for purchase in the US and only on the AfibAlert website.
Interestingly, you cannot purchase AfibAlert without a prescription from a physician.
Why this is mandated for AfibAlert and not AliveCor is a mystery to me.
I’m writing this brief post as a warning to any individuals who have purchased the smartphone app AF Detect (screen shot below from Apple app store.) It is not a reliable detector of atrial fibrillation (AF).
A patient of mine with AF recently purchased this app unbeknownst to me. He relied on its faulty information which reassured hm he was not in AF when in fact he was in AF. Such misinformation has the potential to lead to dangerous delays in diagnosis.
There are multiple reviews on the Apple and Google app sites which confirm the total lack of reliability of this app to diagnose AF with multiple instances of both failure to detect known AF and inappropriate diagnosis of AF when rhythm was not AF.
In the description of the app the company says the app will “transform you rmobile device into a personal heart rate monitor and atrial fibrillation detector”.
However after purchasing the app and before using it you see this disclaimer which states it is not to be used for any medical diagnosis.
I will be performing a more detailed analysis of this app’s performance in the future and contacting the FDA about the danger such inaccurate medical testing confers on victims.
In the meantime if you have any experience with this app or other apps claiming to detect AF reliably using detection of the pulse from finger application to the camera lens please share them with me (via email DRP@theskepticalcardiologist.com or via comments below.)
The skeptical cardiologist has often sung the praises of the AliveCor Mobile ECG for home and office heart rhythm monitoring (see here and here.) However, there is a significant rate of failure of the device to accurately identify atrial fibrillation. I’ve seen numerous cases where the device read afib as “unclassified” and normal sinus rhythm (usually with PVCs or PACs) called afib both in my office and with my patient’s home monitors.
In such cases it is easy for me to review my patient’s recordings and clarify the rhythm for them.
For those individuals who do not have a cardiologist available to review the recordings, AliveCor offers a service which gives an option of having either a cardiac technician or cardiologist review the tracing. The “cardiac technician assessment” costs $9 and response time is one hour. The “Clinical Analysis and Report by a U.S. Board Certified Cardiologist” costs $19 with 24 hour response time.
Obviously, I have no need for this service but I’ve had several readers provide me with their anecdotal experiences with it and it hasn’t been good.
One reader who has a familial form of hypertrophic cardiomyopathy utilizes his AliveCor device to monitor for PVCs. One day he made the following recording which AliveCor could not classify:
He then requested a technician read which was interpreted as “atrial fibrillation sustained.”
He then had requested the cardiologist reading which came back as Normal Sinus Rhythm.
Finally, he again requested the technician read and got the correct reading this time which is normal sinus rhythm with PACs
When my reader protested to Kardia customer service about this marked inconsistency: three different readings in a 24 hour period, a Kardia customer service rep responded :
I was able to review this with our Chief Medical Officer who advised that the recording shows Sinus Rhythm with PACs. The Compumed report seldom provides identification of PACs and PVCs as most cardiologists believe they are not significant findings. The sustained AFib finding was incorrect, so I have refunded the $5 fee you had paid.
Please let us know if you have any other questions.
As I pointed out in my post on palpitations, most PVCS are benign but some are not and patients with palpitation would like to know if they are having PVCS and/or PACs when they feel palpitations.
More importantly, the misdiagnosis of afib when the rhythm is NSR with PACs or PVCs can lead to extreme anxiety.
Heres a recording
I made in my office this morning on a patient with cardiomyopathy and a defibrillator.
This is very clearly NSR with PVCs yet AliveCor diagnosed it as “possible atrial fibrillation.”
The AliveCor algorithm is not alone in making frequent errors in the diagnosis of atrial fibrillation.
The vast majority of ECGs performed in the US come with an interpretation provided by a computerized algorithm and medical personnel rely on this interpretation until it can be verified or corrected by an overreading cardiologist.
One study demonstrated that computerized ECG interpration (ECG-C) is correct only 54% of the time when dealing with a rhythm other than sinus rhythm
Another study found that 19% of ECG-C misinterpreted normal rhythm as atrial fibrillation. Failure of the physician ordering the ECG to correct the inaccurate interpretation resulted in change in management and initiation of inappropriate treatment, including antiarrhytmic medications and anticoagulation, in 10% of patients. Additional unnecessary diagnostic testing was performed based on the misinterpreted ECGs in 24% of patients.
When lives or peace of mind are at risk you want your ECG interpreted by a cardiologist.
I would like to take this opportunity to personally issue a challenge to IBM’s Watson.
Hey, Watson, I bet $1,000 I can Interpret cardiac rhythm from an ECG with more accuracy than you can!
The AliveCor/Kardia mobile ECG device is a really nifty way to monitor your heart rhythm. Since acquiring the third generation device (which sits within or on my iPhone case and communicates with a smartphone app) I have begun routinely using it on my patients who need a heart rhythm check during office visits. It saves us the time, inconvenience (shirt and bra removal) and expense of a full 12-lead ECG which I would normally use.
In addition, I’ve convinced several dozen of my patients to purchase one of these devices and they are using it regularly to monitor their heart rhythms. Typically, I recommend it to a patient who has had atrial fibrillation (Afib) in the past or who has intermittent spells of palpitations.
Some make daily recordings to verify that they are still in normal rhythm and others only make recordings when symptoms develop.
Once my email invitation request is accepted I can view the ECGs recorded by my patients who have AliveCor devices as I described here.
This monitoring has in many cases taken the place of expensive, obtrusive and clumsy long term event monitors.
In general, it has been very helpful but the device/app makes occasional mistakes which are significant and sometimes for certain patients it does a poor job of making a good recording.
Alivecor Success Stories
One of my patients, a spry ninety-something year young lady makes an AliveCor recording every day, since an episode of Afib 9 months ago.
And when I say every day I mean it literally everyday. It could be because she is compulsive or perhaps she has programmed the AliveCor to remind her. When I log in to the AliveCor site and click on her name I can see these daily recordings:
After a month of normal daily recordings, she suddenly began feeling very light headed and weak with a sensation that her heart was racing.
She grabbed her trusty iPhone and used the AliveCor device attached to it to make a recording of her cardiac rhythm. This time, unlike the dozens of other previous recordings, the device indicated her heart rate was 157 beats per minutes , about twice as fast as usual.
After 5 hours her symptoms abated and by the time of her next recording she had gone back to the normal rhythm.
She made two other recordings during the time she felt bad and they both confirmed Afib at rates of 140 to 150 beats per minute.
In this case, the device definitely alerted her to a marked and dramatic increase in heart rate but was not capable of identifying this as Afib In my experience with several hundred recordings, the device accurately identifies atrial fibrillation about 80% of the time. On rare occasions (see here) it has misidentified normal rhythm with extra beats as atrial fibrillation
AliveCor/kardia users have the option of having their recordings interpreted for a fee by a cardiologist or a technician.
My patients can alert me of a recording and I can go online and read the ECG myself and then contact the patient to inform them of my interpration of their heart rhythm and my recommendations.
Another patient made the recording below:Although she is at high risk of having a stroke during the times she is in Afib, we had been holding the blood thinner I had started her on because of bleeding from her mouth. I had instructed her to take daily recordings of her rhythm with the AliveCor until she was seen by her dentist to evaluate the bleeding.
In this case, the AliveCor performed appropriately, identifying correctly the presence of Afib which was the cause of her nocturnal symptoms.
A young woman emailed me that her AliveCor device on several occasions has identified her cardiac rhythm during times of a feeling of heart racing and palpitations as “possible atrial fibrillation.” When she sent the recordings in to AliveCor to have a paid interpretation, however, the recordings were interpreted as sinus tachycardia with extra beats. Indeed , upon my review her rhythm was not Afib. Clearly, when the device misidentifies Afib, this has the potential for creating unnecessary anxiety.
It is not uncommon for a full, 12-lead ECG done in the hospital or doctor’s office by complex computer algorithms to misinterpret normal rhythm as Afib so I’m not surprised that this happens with AliveCor using a single lead recorded from the fingers.
The young woman was advised by AliveCor to try a few things such as using the device in airplane mode, sitting still and wetting her fingers which did not help. She was sent a new device and the problem persisted. She finds that putting the device on her chest gives a better chance of success.
She also runs into a problem I see frequently which is a totally normal recording labeled by the device as “unclassified.”
In this example, although I can clearly see the p-waves indicating normal sinus rhythm, the voltage is too low for the device to recognize.
Send Me Your AliveCor Problems and Solutions
I’m interested in collecting more AliveCor/Kardia success and failure stories so please post yours in the comments or email me directly at DRP@theskeptical cardiologist.com.
In addition, I’m interested in any tips AliveCor users have to enhance the success of their recordings: What techniques do you use to make the signal strength and recording better? What situations have you found that tend to worsen the signal strength and recording quality?
Still Unclassified Yours,
P.S. Tomorrow is Cyber Monday and I note that Kardia is running a “Black Friday” special through 11/28, offering the device at 25% off.
P.P.S. Kardia, You should change the statement on your website, “90% of strokes are preventable if you catch the symptoms early.” makes no sense. I think you mean that some strokes are preventable (I have no idea where the 90% figure come from) if one can detect Afib by utilizing a monitoring device to assess symptoms such as palpitations or irregular heart beat.
The skeptical cardiologist likes to see his afib patients stay in the normal rhythm (normal sinus rhythm) after they are cardioverted. On Halloween here in the office at Cardiac Specialists of St. Lukes three of our assistants helped drive home the message with a creative ensemble costume:
Speaking of Halloween, rather than handing out candy next Halloween, I’ll be handing out sacks of stroke-bustin’ nuts.
I’m sure the neighborhood kids will love the alternative to all that high fructose corn syrup!
For many proceduralists in medicine and surgery, there is a tendency to overestimate the value and underestimate the risk of the intervention that they perform. This factor, plus the current medical reimbursement system in the US, which rewards physicians primarily on the quantity of services performed rather than the quality of care, fosters a strong incentive for proceduralists to perform their procedures early and often.
It is rare for a proceduralist to publicly advocate a cautious and circumspect approach to their procedure; the usual public expressions are highly enthusiastic endorsements intended for marketing and increasing volume.
In this regard, it is particularly refreshing to read the thoughts today of a clinical electrophysiologist, whose bread and butter partially consists of doing ablations of atrial fibrillation (AF.)
John Mandrola (who writes a great blog at DrjohnM.org and reports for theheart.org) has written an excellent summary of the things that patients should consider prior to getting an AF ablation which I shall reblog below.
Mandrola asks us to consider whether the decision for AF ablation should be made by a team rather than by the proceduralist who stands to benefit from performing the ablation.
I’ve emphasized some points from his post:
-AF ablation is a multi-hour procedure that requires general anesthesia. Up to 80 burns are made in the left atrium, some close to the esophagus and phrenic nerve. There are significant risks to the procedure. The honest long-term success rate barely tops 50%.
-Many patients have to undergo a second procedure, or even third or fourth procedures.
-Some questions an AF team might ask:
Have you checked the patient for sleep apnea?
Have you asked him to reduce his alcohol intake or weight?
Will the AF resolve after the stress of a divorce has worn off?
Does the patient know there’s not a shred of evidence that AF ablation reduces stroke or death rates?
-Does the patient know that AF is not deadly heart disease? In other words, has fear been sufficiently extracted from the decision?
I, not infrequently, refer appropriate patients to excellent and thoughtful electrophysiologists for a discussion of the pros and cons of ablation and consideration of its performance . Before sending them, I try to act like the “team” that Mandrola envisions and review the risks and benefits along with alternative approaches.
A patient presents with atrial fibrillation (AF) and a rapid rate. He doesn’t know he is in AF; all he knows is that he is short of breath and weak.
The doctors do the normal stuff. He is treated with drugs to slow the rate and undergoes cardioversion. During the hospital stay, he receives a stress test and an implantable loop recorder.
He goes home on a couple of medications. The expensive implanted monitor shows rare episodes of short-lived AF, less than 1% of the time. The patient feels great.
But here’s the kicker: his doctor recommends an AF ablation.
This is nuts. The man has had one episode of AF. He has no underlying heart disease. And he feels well while taking only basic meds. There’s been no discussion of weight loss, exercise, alcohol reduction, or sleep evaluation.
I don’t know how often this happens in the real world, but I suspect that it’s happening more and more. The number of doctors trained in electrophysiology have increased. And, trainees in academic centers spend most of their time mastering the AF ablation procedure.
The Dartmouth Atlas of Healthcare group have shown cardiology to be a supply-sensitive service. Meaning, the more cardiologists there are in an area, the more procedures get done. This build-it-and-they-will-come problem dogs much of US healthcare, not only cardiology. Think MRI and CT centers.
Might a solution to the overuse of AF ablation be a multi-disciplinary heart team?
We already do this for some heart valve surgeries, specifically, transaortic valve replacement (TAVR).
AF ablation is a multi-hour procedure that requires general anesthesia. Up to 80 burns are made in the left atrium, some close to the esophagus and phrenic nerve. There are significant risks to the procedure. The honest long-term success rate barely tops 50%. (Success rates depend somewhat on the type of AF.)
Then there are the repeat procedures. Many patients have to undergo a second procedure, or even third or fourth procedures. (All at many thousands of dollars per case.)
If doctors recommending the procedure had to present the patient to a team of peers, there may be more discussion about the sobering realities of AF care. Questions could arise:
Have you checked the patient for sleep apnea?
Have you asked him to reduce his alcohol intake or weight?
Will the AF resolve after the stress of a divorce has worn off?
Does the patient know there’s not a shred of evidence that AF ablation reduces stroke or death rates?
Does the patient know that AF is not deadly heart disease? In other words, has fear been sufficiently extracted from the decision?
I recognize that not every decision in medicine should be made by committee. AF ablation, however, might fit some sort of internal review.
The European Heart Journal just published a terrific review on the treatment of persistent AF. In this paper, the treatment of risk factors gets strong mention–as does the sobering results of AF ablation in more advanced forms of AF, and the vast uncertainty surrounding treatment approaches.
I’m not against AF ablation; I perform the procedure often. But after I’m sure all other aspects of atrial-health have been addressed, and the patient is fully informed. It’s a huge mistake to equate AF ablation with ablation of other focal (emphasis on focal) rhythm problems, like supraventricular tachycardia.
I’d have no trouble justifying my AF ablation procedures to a heart team.
The skeptical cardiologist received an email from the folks at AliveCor a few days ago with the subject line:
Dad’s heart matters – Kardia Mobile for Dad will give you peace of mind and make Dad happy
The email contains this image of an older well-dressed man (with lots of bling) standing in a beautiful meadow near the ocean. The man has decided to turn his back on the ocean and check his heart rhythm using the AliveCor/Kardia (AliveCor has changed the name of its ECG devices to Kardia) mobile ECG. This man is a happy dad! (Unless his heart rhythm is interpreted as atrial fibrillation. Then the beach walk is ruined.)
The email asks the question “What if Dad’s heart really was an open book?”
Uhh, he’d be dead? Clearly books don’t function well at pumping 5 or 6 liters of blood through the cardiovascular system every minute whether they are open or closed. Perhaps the question is using either the heart or an open book as a metaphor?
The advertisement goes on to suggest that I get my dad an AliveCor device for father’s day “So you always know what his heart is thinking.”
I believe this is the marketing person’s attempt to extend the metaphor of the open book, i.e., you know exactly what dad’s brain is thinking, now you can extend this knowledge to his heart. The metaphor of the heart “thinking” is quite poor but poor metaphors are the norm today.
Bad metaphors and bad writing abound on father’s day because 90 million greeting cards are purchased and given as (according to the Greeting Card Association) “a meaningful expression of personal affection for another person.” Despite the increasing use of Facebook and its ilk to transmit emotions, the Greeting Card Association assures us that “The tradition of giving greeting cards … is still being deeply ingrained in today’s youth, and this tradition will likely continue as they become adults and become responsible for managing their own important relationships.
Mobile Ecg Monitor As A Father’s Day Gift
I have to say that despite the horror of the writing in this email advertisement it got me thinking about getting my father a Kardia device. I’ve suggested previously that an AliveCor device would make a good gift for Christmas for a loved one who has intermittent unexplained palpitations or atrial fibrillation but had not considered this for my dad.
For one thing he does not possess a smart phone which is required to make the Kardia device functional. For another, he doesn’t have atrial fibrillation (that we know of. Perhaps if I knew what his heart was thinking we would find out that it likes to fibrillate late at night,)
Perhaps it’s time to upgrade my Dad to an iPhone I began thinking.
But wait! He has an iPad mini (that he seems to only use for FaceTime conversations.)
Further research reveals that Kardia is not only compatible with iPhone and Android smartphones but apparently iPads and IPod Touch.
Taking Care of Dad’s Heart
What about the rest of the slick advertising copy in my email?
And now you can know the way to help take care of it. Kardia gives Dad a medical-grade EKG in only 30 seconds. It even gives him expert analysis and tracking, with reports getting shared directly with his physician
This part is pretty clear and correct. I use Kardia daily in my office to record patient’s heart rhythm and I have a dozen patients now who make recordings outside of the office. They can have their recordings read by a random cardiologist for a fee or establish a link with me as their provider and I can review them through my account for free.
Is It The First Father’s Day Gift That Leads To More Father’s Days?
The ad ends with the remarkably brazen statement that “It’s the first Father’s Day gift that leads to more Father’s Days.”
While I find the device more helpful in many instances than current expensive and intrusive long term monitoring devices for detecting and monitoring atrial fibrillation and other abnormal heart rhythms, it is a huge leap to suggest that this translates somehow into a longer life span.
To AliveCor’s credit, despite such ridiculous marketing drivel , studies presented at the recent Heart Rhythm Society Scientific Meetings suggest:
Kardia Mobile Superior to Conventional Monitoring: Researchers at the Leeds General Infirmary found that the AliveCor monitor is superior to conventional Holter monitoring in patients with palpitations, providing a higher diagnostic yield, more detected arrhythmias, with a similar workload.
Kardia Mobile Leads to Improved Patient Compliance:Researchers at the University of Buffalo found that AliveCor provides a diagnostic yield comparable to a 30-day ambulatory looping event monitor and that the smartphone-based ECG monitor can be used as a first approach for the diagnosis of palpitations.
Kardia Mobile provided more information resulting in changes in arrhythmia patient management than traditional external event recorders in a study from researchers at the University of Miami.
AliveCor’s AF algorithm was reported to be superior by researchers at Arizona State University to the patient’s own ability to detect AF via symptoms.
But even if these studies make it to publication they don’t suggest the device provides any improved longevity. In fact, such data, do not exist for any monitoring device.
Happy Father’s Day, Dad! Don’t be surprised when we FaceTime later today that I’ve found another use for your iPad.
N.B. Clearly I receive no consulting, speaking or P.R. writing fees of any kind from AliveCor. Nor do they provide me with any free devices. What’s more, when I lose one of their devices they don’t replace it. I am totally free of any conflict of interest.
In a previous post, the skeptical cardiologist was dealing with a patient about to embark on a 16 day cruise through the Panama Canal who was having frequent episodes of atrial fibrillation.
I was concerned about the medical care on board her cruise ship and had not been able to contact medical personnel on board.
I’m happy to report that I have been in email contact with Dr. C, of Celebrity Cruise Lines who is on board the Celebrity Infinity as it sails down the Pacific coast of Mexico and prepares to dock in Cabo San Lucas today.
Dr. C tells me that they have excellent medical personnel and resources available and should my patient go into afib they will be very comfortable dealing with the situation:
“Well I can not speak for any other cruise line but Celebrity, Royal Caribbean and Azamara (the 3 are part of Royal Caribbean Intl), which I have work on the 3 lines. As requirements for the Physicians and Nurses is to have BLS, ACLS, PALS and ATLS certification every 2 years, but most of us like to perform it at least once a year. Most of the ships have 2 Physicians and 3 Nurses, except the Oasis class ships, where there are 3 Doctors and 5 Nurses.
Regarding equipment, we have the necessary equipment to stabilize cardiac emergencies (obviously not all of them)… we have the mentioned monitors with described capabilities, a portable pressure/volume ventilator (used in the US Army in areas of combat). For IV cardiac medications, we have Adenosine, epinephrine 1:1000 and 1:10000, atropine, amiodarone, procainamide, dopamine, dobutamine, furosemide, metoprolol, diltiazem, verapamil, labetalol, digoxin, calcium gluconate and chloride, furosemide lidocaine 2%, magnesium sulfate, norepinephrine, sodium nitroprusside, nitroglycerine, enoxaparin, clopidogrel (oral), aspirin and tenecteplace as fibrinolytic.”
What Is The Scope Of Cruising Cardiac Emergencies?
After publishing my last post , Dr. Sergio Pinski tweeted me a link to a paper from 2010 entitled “Cardiovascular Emergencies in Cruise Ship Passengers” that he co-wrote.
The Cleveland Clinic Florida apparently provides “contracted cardiology consultations” to cruise ships and they recorded the nature and outcome of their consultation over a two year period.
“One hundred consecutive patients were identified (age 66 +/- 14 years, range 18 to 90, 76% men). The most common symptom was chest pain (50%). The most common diagnosis was acute coronary syndrome (58%; ST elevation in 21% and non-ST elevation in 37%). On-board mortality was 3%. Overall, 73% of patients required hospital triage. Of the 25 patients triaged to our institution, 17 underwent a revascularization procedure. One patient died. Ten percent of patients had cardiac symptoms in the days or weeks before boarding; all required hospital triage. Access to a baseline electrocardiogram would have been clinically useful in 23% of cases.”
As a result of these observations they recommended the following:
“A pre-travel medical evaluation is recommended for passengers with a cardiac history or a high-risk profile. Passengers should be encouraged to bring a copy of their electrocardiogram on board if abnormal.”
Finally, the authors write (and this seems a little self-serving and not supported by data) that:
“Cruise lines should establish mechanisms for prompt consultation and triage.”
Dr. Pinski also tells me he has witnessed two electrical cardioversions performed onboard cruise ships.
I don’t know if Cleveland Clinic is consulting with my patient’s ship but I’d prefer cardioversions be done on land, preferably in a hospital with appropriate anesthesia (see my post on defibrillation).
More Research Needed: Volunteers Saught
If any of you are aware of cardiac emergencies or episodes of atrial fibrillation on cruise ships and how they were handled please let me know. I’ll collect as much first hand information as I can and share it with you.
In my office this morning I spoke with an afib patient who is planning on a several week cruise in the Mediterranean on a Royal Caribbean ship. He has agreed to be my investigative reporter on the status of medical care on that cruise.
I don’t know if you can expect this level of cardiac medical care on every cruise but it makes sense, if you are a heart patient, to find out what is available in terms of medical personnel, cardiac and pulmonary monitoring/pacing/cardioversion equipment and medications should you go into afib or another cardiac emergency on your particular ship.
Finally, ask the cruise company if they contract for cardiology consultation services with any entity and, if so, what that entity is and how the consultation works.
The most effective method for getting a heart that is in atrial fibrillation back to normal rhythm is a called an electrical cardioversion.
I’ve tried to come up with a good alternative or descriptive term for this procedure for my patients, such as “resetting” or “rebooting” the heart, but the term that seems to best resonate with patients is “shocking” the heart.
How Does Electrical Cardioversion Work?
Typically, we all can connect (excuse the pun) to the feeling of a low current electrical shock which occurs when touching an ungrounded electrical source.
Unless the current reaches a certain level, it only results in transient burns and discomfort.
However, at current levels greater than 50 mA, an AC electrical shock traveling through the chest can, if timed properly, cause the heart to go out of normal rhythm into ventricular fibrillation.
We use a “synchronized” electrical cardioversion (termed direct current or DC cardioversion (DCC)) to convert a fibrillating or fluttering atrium back to the normal rhythm by timing the electrical shock so that it doesn’t cause ventricular fibrillation but resets both ventricles and atria safely back to normal.
This may seem like a barbaric and unnecessarily crude and dramatic way to restore normal rhythm, but if patients are properly prepared for this procedure, it is very safe and very effective, resulting in resumption of the normal rhythm 99% of the time.
There are some medications that we can utilize to convert atrial fibrillation (afib) back to normal (antiarrhythmic drugs), but they are far less effective than the electrical cardioversion, and often can bring out more dangerous heart rhythms.
Typically, I do my cardioversions in conjunction with an anesthesiologist, who administers IV propofol (yes, this was Michael Jackson’s sleep aid, his “milk”) to obtain “deep sedation.” At this level of anesthesia, the patient is breathing on his own but will only respond to painful stimulation. The propofol is short-acting and prevents the patient from feeling the intense pain of the cardioversion (often described as like a mule kicking one in the chest), and from recalling any of the events.
The electrical shock is administered through electrodes, consisting of large sticky pads with electrical conducting gel attached to the right anterior chest and the left posterior back (see this brief information from Zoll about optimal placement).
Since I began using “biphasic” energy, the initial cardioversion is successful >95% of the time in my experience, but the heart may revert back to atrial fibrillation anywhere from a few minutes to a few years after the shock. We can reduce the chances of reverting back by the use of anti-arrhythmic drugs.
Multiple Shocks: What Is The Limit?
The DCC may need to be repeated, and we may repeat it after starting one of those anti-arrhythmic drugs I mentioned, in order to increase the time that the heart stays in the normal rhythm.
A common question when I recommend a repeat cardioversion is:
“Doc, how many times can you have your heart shocked?”
One might think it is one and done with the shock but it is not a cure; it is merely a resetting of the chaotic, confused and futile activity of the atria, so that the synchronized and regular electrical pacing provided by the sinus node in the upper right atrium can again resume its rightful role as conductor of the cardiac electrical orchestra that creates the wondrous symphony of normal cardiac contraction.
The factors that brought on the afib in the first place likely are still present: if we don’t address correctable factors we are less likely to maintain the normal sinus rhythm (NSR). Correctable factors include:
abnormal thyroid function
abnormal potassium or magnesium
inflammation of adjacent lung or pericardium
obesity (see my post on fat sheep and afib)
certain cardiac valve problems
There is no evidence that the cardioversion per se damages the heart in any way. The major risks of the procedure (again, assuming proper preparation, see below) are related to the anesthesia.
I am more inclined to recommend a repeat cardioversion if there is clear-cut evidence that the patient does poorly when the heart is in afib.
Why Shock The Heart?
In medicine, there are two reasons for giving medications and doing surgery/procedures: to make the patient feel better or to reduce the chances of dying/having a major complication.
The major complication of afib is stroke. Proper anticoagulation is required to prevent this in patients with afib whether or not they are in normal rhythm. Clots can form in the left atrial appendage within hours of the development of afib, and the electrical cardioversion can increase the chance of stroke as any clot present is more likely to be expelled when the quivering, ineffective atrium converts back to a normally pumping, vigorous atrium.
Primarily, then, we utilize cardioversion for the purpose of making patients feel better.
Some patients feel terrible the moment they go into afib: symptoms of palpitations, chest pain, or shortness of breath predominate and are especially prominent if the heart rate is high. Controlling the high heart rate with beta-blockers or diltiazem will reduce many of these symptoms, but I have a large number of patients who still feel terrible when they are “out of rhythm,” even if the heart rate is normal. Such patients who persist in afib are good candidates for one or multiple cardioversions, with or without the addition of anti-arrhythmic drugs.
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.
Multiple Shocks: Rationale
Yesterday I did an electrical cardioversion on an elderly patient of mine for atrial fibrillation/flutter; this was her fifth DCC in the last year.
She falls into the second category of afib patients; she had developed severe heart failure due to mitral regurgitation after silently going into afib a year earlier. After long-term loading on the anti-arrhythmic drug amiodarone, followed by her fourth cardioversion, she had stayed in NSR for 10 months, her MR resolved, and she felt great. In patients like her, I think it is particularly important to maintain NSR and thus, multiple shocks are definitely warranted.
On the other hand, if you feel fine in afib without any evidence that it is effecting your heart muscle or valves, then it is hard to justify multiple attempts to shock the heart.
Any patient that has recurrent symptomatic afib or afib associated with heart failure, should be considered a candidate for an atrial fibrillation ablation. The risks and benefits of afib ablation are worthy of another blog post, but the patient-centered afib website stopafib.org has a reasonable discussion here. Suffice it to say, it is a much more complicated and risky procedure than a cardioversion, but it attempts to address the underlying cause(s) of afib, and in some cases creates what could be considered a “cure.”
It has for the most part taken the place of the more elaborate, but cumbersome and time-consuming, 12-lead ECG in patients where heart rhythm is my only concern.
I’ve also convinced about a dozen of my patients who have intermitent atrial fibrillation to obtain the device and they are actively using it to monitor at home their heart rhythm. Through the AliveCor website, I can view their recordings and see what their heart rhythm is doing when they have symptoms.
Last week, a patient of mine (I’ll call her Suzy) who has had significant prolonged episodes of atrial fibrillation associated with heart failure (but cannot tell when she is in or out of rhythm) notified me that her device was interpreting her rhythm as atrial fibrillation. She had not had any symptoms, but was making daily recordings for surveillance.
Suzy called our office and we brought her in the next day and confirmed with a 12-lead ECG that she was indeed in atrial fibrillation with a heart rate of 120 beats per minute.
It’s pretty amazing that this little, inexpensive device can now replace expensive and elaborate long term cardiac monitors for many of my patients.
AliveCor Rebrands Itself to Kardia
I’ve noticed that AliveCor has rebranded itself as Kardia. If you go to http://www.alivecor.com now you see the fourth generation device along with promotion of a “Kardia band” which apparently works with an Apple Watch to record your ECG.
The Kardia band is not available for purchase at this time but if and when I can get one, it might motivate me to purchase an Apple watch.
When I purchased my AliveCor device in June, 2015 it cost $74.99 from Amazon.com. The newer version is priced at $99 at both AliveCor and Amazon websites. I’m told by Dr. David Albert of AliveCor that this “fourth generation” version is more accurate, so I have purchased it to see if it reduces the problem of occasional bad recordings.
You can see in this picture from the website that the formerly flat metal electrodes now have bumps. Dr. Albert says these result in more surface area for better contact with skin. We will see.
The Value of Early Detection Of Atrial Fibrillation
Meanwhile, I will be doing an electrical cardioversion (shocking or resetting the heart) on Suzy to get her back to normal sinus rhythm. If we had not detected the asymptomatic onset of her rapid atrial fibrillation using the AliveCor/Kardia device, chances are we wouldn’t have known about it until her heart muscle weakened again and she became short of breath from heart failure.
I have Suzy on blood thinners to lower her risk of stroke associated with her Afib but for my patients who are not on blood thinners, detection of silent or asymptomatic AFib is even more important.
p.s. The skeptician in me feels this post borders on infomercialese.
Let me make it clear that I have no connection with the company formerly known as AliveCor and have received nothing from them (not even free test devices or Apple Watch Kardia Bands!) but I’m just really excited about the device and how it can help my patients (oh, please excuse me, this really sounds like marketing) “empower” themselves to take control of their heart rhythm.
In the course of writing this, I’ve discovered an academic paper evaluating 13 ECG smart phone type ECG devices so there are other devices you could try. I haven’t had the time or resources to evaluate them.