Last week I wrote a column on theheart.org | Medscape Cardiology on the new Apple Watch ECG and Kardia Band.
The Tweet I sent out on Saturday has done well — 74 Retweets (without any robots) is pretty good.
— John Mandrola, MD (@drjohnm) December 9, 2017
Here is an overview of some of the points I made in the column.
One is that Apple’s interest in AF is huge. The company has partnered with Stanford researches and has started the Apple Heart Study. Any owner of an Apple Watch can volunteer to participate.
The excitement of mobile ECG technology is that it allows for rhythm screening–mostly AF. The thinking: stroke is a major health problem; AF associates with stroke and we have treatments (anticoagulants). Thus it would be good to know one’s heart rhythm.
You know how simple thinking about screening works in medicine. Yes, there are snags. One problem now is accuracy. In the column, I attached two AliveCor tracings that mistakenly labeled premature beats as AF. Both patients suffered anxiety from the fake AF.
I did list many upsides of mobile ECG technology.
- Marc Cuban himself tweeted on my timeline that he had AF and likes the peace of mind of knowing what his rhythm is.
- A man from Romania, where access to doctors is less than it is here, made the point that mobile ECGs allowed him to get faster responses from doctors.
- My friend Dr. Gopi Dandumudi from IU believes that empowering consumers to be involved in their healthcare is a good thing in the long run.
- And I have often prescribed the AliveCor to confirm diagnoses and monitor for side effects from drugs.
Indeed the device is useful for specific tasks.
Of course, its proponents (and marketing team) hype it as a revolutionary tool for health. This may be true someday, but I have many concerns in the interim.
Here are four challenges.
One is that the causal link between AF episodes and stroke is less certain than you may think. This argument gets complicated. There was once a researcher named Bradford Hill who came up with nine criteria that should be fulfilled if one factor is thought to cause another.
AF does fulfill some of these criteria, but it clearly does not fulfill others. For instance, one of Hill’s criteria is correlation in time. AF fails this criteria because there are multiple studies showing poor correlation between the timing of AF episodes and stroke event. (I explain more in the column.)
Another challenge is that we don’t whether clot-blocking drugs (anticoagulants) will benefit patients with shorter-lived or non-symptomatic AF (EPs say subclinical AF) in the same way it does those patients with longer-lasting or symptomatic AF. The studies showing anticoagulant benefit were done in people with clinical AF or AF seen on multiple, regular in-office ECGs.
The reasons to doubt anticoagulants will benefit many of the people with short-lived AF is that plenty of studies observe very low untreated stroke rates in these patients. That is key because it’s hard for any treatment to lower an already low event rate. Remember, too, anticoagulants don’t come free: they do increase the risk of bleeding. No doubt these drugs are beneficial in higher stroke-risk patients, but the mobile ECG will greatly expand the pool of lower-risk people.
The most scary challenge of the mobile ECG is that the greater numbers of AF diagnoses will occur in a US healthcare system that pays hospitals and doctors to test and treat. If you combine fee-for-service payment models and most doctors’ fear of anything heart related, it’s easy to predict a massive increase in overtreatment and overdiagnosis. Think here of the children’s book: If you give a mouse a cookie. Proponents rightly point out that this problem is not the fault of technology.
Finally, the big problem with any new technology is its ability to distract us. Here I believe the distraction is from already proven ways to prevent stroke: read the article. I explain what those are.