The Skeptical Cardiologist was quite enthusiastic about AliveCor's for Apple Watch since its release late in 2017.
I was able to easily make high-fidelity, medical-grade ECG recordings with it, and its artificial intelligence algorithm was highly accurate at identifying atrial fibrillation (AFib, see ). This accuracy was subsequently confirmed by .
Many readers spent $200 for the KardiaBand and found it to be very helpful in the management of their atrial fibrillation.
However, in December 2018, Apple added ECG recording to its Apple Watch 4 (AW4), essentially building into the device the features that KardiaBand had offered as an add-on to earlier versions of the Apple Watch.
In my 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 yielded more uncertain diagnoses in comparison to AliveCor's.
Given its size, prominence, and vast resources, Apple's very publicized move into this area seemed likely to threaten the viability of AliveCor's KardiaBand.
But then-interim CEO (and current chief operating officer) Ira Bahr later told 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," . "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 and its are doing very well. But the threat to the viability of KardiaBand was real, and MobiHealthNews announced on Aug. 19 that AliveCor had officially ended sales of the KardiaBand:
"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 ."
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 noted, "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 KardiaBand provided a valuable convenience over their other products."
It does appear that Smart Rhythm is no more.
AliveCor's website was updated last week to state that Smart Rhythm was discontinued "due to changes beyond our control in the Apple Watch operating system, which caused Smart Rhythm 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, 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. I critiqued that study , noting that of the subset of participants who received an irregular rhythm notification on their Apple Watch while simultaneously wearing an ECG patch, 80% showed AFib on the ECG patch and 98% showed AFib or other clinically relevant arrhythmias.
Despite widely publicized reports of lives being saved by this notification feature, 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 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 it 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 competition in this area would make for better products and more accountability.
Per AliveCor, the KardiaBand currently works with all Apple Watches, except the original one.
The Apple irregular rhythm notification feature, per Apple, "is available for Apple Watch Series 1 and later and requires iPhone 5s or later on iOS 12.1.1 in the U.S., Puerto Rico, Guam and U.S. 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."
Please also note that I have no financial or consulting ties to AliveCor. I'm just a big fan of their products.
is a private practice noninvasive cardiologist and medical director of echocardiography at St. Luke's Hospital in St. Louis. He blogs on nutrition, cardiac testing, quackery, and other things worthy of skepticism at , where a version of this post first appeared.
Disclosures
Pearson declared he had no conflicts of interest relevant to this article.