An EKG on the wrist seems like a good idea, it may not.

“We have added electrodes on the back sapphire crystal and on the digital crown, allowing you to take an EKG.” With those words Jeff Williams provoked a huge standing ovation during Apple’s (now traditional) annual event. And the thing is as it sounds, Tim Cook and his team they have got an electrocardiogram on Apple Watch Series 4.

In principle, the idea sounded great. Ivor J. Benjamin himself, president of the American Heart Association, spoke at the same event about the advantages it could bring the democratization of access to the electrocardiogram. However, the real question is whether those supposed benefits outweigh the potential problems. And, from what we know so far, the answer appears to be no.

An EKG on the wrist seems like a good idea, it may not

An EKG on the wrist

In November 2017, the FDA approved the KardiaBand for AliveCor and the company advertised it as the “first medical accessory for the Apple Watch.” It was a big step: usually, getting the ‘OK’ from the FDA is very complex and, with this, a lot of possibilities were opened wide.

It is also something that limits (at least geographically) Apple’s announcement. The functionality will arrive in the US throughout the year, but will not make it to the rest of the world until regulatory agencies approve the device. Wanting a medical device entails times that are very far from those that the world of technology has accustomed us to.

An EKG on the wrist seems like a good idea, it may not

KardiaBand allows you to monitor the heart system for thirty seconds by measuring the constants at the wrist. In addition, the KardiaBand connects to an application that allows assess changes in heart rate in real time and notify the user as soon as there is a problem.

In terms of accuracy, it is not a Holter (an ambulatory electrocardiogram), nor – from what you can read in the FDA clearance – does it pretend (despite the bombastic publicity they have been doing). The KariaBand is not intended to perform a comprehensive EKG analysis – it is to take “snapshots” that can help clinicians study cases in greater depth. And this can come in handy for certain people with a family history of heart disease or risk factors. But, above all, to people with atrial fibrillation.

An EKG on the wrist seems like a good idea, it may not

A solution for a very specific problem

Atrial Fibrillation occurs when the movement of the atria (the upper chambers of the heart) becomes uncoordinated and produces an irregular heart rhythm. It’s not just about the most common heart disease (It is estimated that it originates 3.6% of general emergencies and more than 10% of hospital medical admissions); is that, in fact, it becomes more common with age (going from 1% in young people to 10% in the elderly).

AF tends to have thromboembolic complications (an increase in the risk of stroke and mortality), so an early diagnosis that allows it to be under control is of interest. The problem is that, there are types of AF that are difficult to diagnose. It is estimated that up to 65% of AFs can be of the ‘paroxysmal’ type; that is, their seizures last less than 2 minutes and, for this reason, it is almost impossible to study with an ECG.

An EKG on the wrist seems like a good idea, it may not

Although the latest reviews indicate that paroxysmal AF are not clearly associated with the risk of thromboembolism and death, they are cause great discomfort, anxiety and worry. Especially when patients notice fibrillation and know that “something is wrong.” Here, the 30 seconds of the Apple Watch can be useful (because they allow you to take a snapshot of the crisis).

Beyond, all problems

For everyone else, I’m afraid, the evidence suggests that the problems associated with EKG use outweigh the benefits. And this is not a new debate. Quite the contrary, the usefulness of electrocardiographic screening has been discussed for a long time. That is, to do ECGs in asymptomatic adults with a low risk of heart disease just because.

In 2012, the US Preventive Services Task Force had already recommended do not carry out this type of screening. And a few months ago he did it again.

An EKG on the wrist seems like a good idea, it may not

Why? Because even on the assumption that some cases that remained hidden are discovered; for the vast majority of people there will be no benefit to screening. Of course, the false positives subject patients to the negative impact of anxiety and unnecessary treatments. That is the predictable result of having a wrist ECG.

Addenda: the case of the thermometer

With good judgment, the name suggests in comments that thermometers or tensiometers would be in a very similar situation and I find it interesting enough to add my answer to the post.

At the beginning of this article I myself commented that “the new Apple Watch Series 4 is a perfect metaphor for all the problems and opportunities of digital medicine that is about to arrive.” Because the unnameable is not wrong, the case of thermometers and tensiometers is identical. Health recommendations also do not recommend taking temperature or blood pressure to asymptomatic adults at low risk of disease.

An EKG on the wrist seems like a good idea, it may not

‘Having a fever’ does not mean the same in analog medicine as in digital medicine

Thermometers are used when there are signs of fever; blood pressure monitors, when there are problems with blood pressure (or risk factors) and we need to monitor their evolution. In the same way, nothing prevents having a device to make electrocardiograms at home. What changes with digital and wearable medicine is that ** those instruments stop being used when they are indicated ** to always be used.

The ‘medical literacy’ (that is, the algorithms and heuristics that we have about what to do when we encounter ailments or discomforts) are adapted to our current technical systems. This means that when technology changes, our way of understanding health must also change. Trivial things like ‘having a fever’ does not mean the same in analog medicine as in digital medicine.

Today, and that is the consensus of medical institutions around the world, systems such as the Apple Watch may have a role in investigating cardiac function, but they do not contribute much at a therapeutic level. Moreover, in addition, cause more unnecessary harm than good. And that is a problem that we must learn to manage (because this technology is here and is not going anywhere).

An EKG on the wrist seems like a good idea, it may not