Garmin edges closer to releasing a watch with ECG & blood pressure, new patent

Wearable brand Garmin has just registered a patent with the US Patent & Trademark Office (USPTO) for a watch that can track ECG and potentially blood pressure, as well.

What is an ECG?

An electrocardiogram (ECG) is a test that is used to check the health of your heart’s rhythm and electrical activity. The tech is often used to diagnose symptoms of a possible heart problem, such as arrhythmias, coronary heart disease, heart attacks and cardiomyopathy.

Essential reading: Keep tabs on your heart – wearables the come with an ECG sensor

In the doctors office, a test involves attaching a series of electrodes to your arms, legs and chest. These sensors lead from your body to an ECG recording machine.

Previously you could only take ECGs in medical settings or by purchasing a bulky machine. That has changed in recent years. You could say, home-ECG monitoring has been popularized by the Apple Watch. Series 4 and above come with the tech built in allowing anyone to keep an eye on their heart health from the comfort of their living room.

This works on demand. Users are meant to launch the ECG app and rest their finger against the digital crown on the Apple Watch. This creates a closed circuit with the sensor on the back and then the electrodes work in tandem to capture electrical impulses from the heart.

But Apple is not the only wearable brand with ECG monitoring. There are others such as Withings, Fitbit and Samsung, plus a number of less well known options.

What you’ll notice is that Garmin is not on this list. Unlike some other wearable brands, Garmin has not yet integrated ECG into its products. Well, that might be about to change.

Garmin is working on a single-lead ECG device

In April last year, Garmin launched a Clinical Trial to determine whether its proprietary ECG technology is any good. This is how the study is described in the US National Library of Medicine.

“The purpose of the study is to confirm the Garmin ECG (electrocardiogram) software algorithm can detect and classify atrial fibrillation and normal sinus rhythm on single lead ECG data derived from a Garmin wrist-worn, consumer device.

The study will also confirm the software’s ability to create a Lead I ECG that is clinically equivalent to a reference device. The Garmin ECG software is not a diagnostic system and is intended for informational purposes only.”

The most interesting part of this description is that it clearly states the single-lead ECG device is a Garmin “wrist-worn, consumer device”. Single lead data is what is typically derived from smartwatches with ECG technology. This is less accurate than 12-lead ECGs, which is what you typically get in a medical setting.

Nevertheless, studies have shown that single-lead smartwatches do a decent enough job when measuring ECG from the wrist. One such study published in BMJ Journal shows that such wearables offer “moderate diagnostic accuracy when compared with a 12-lead ECG”. And suggest that “physician involvement will likely remain an essential component when exploring the utility of these devices for arrhythmia screening.

Looking out for Afib

Garmin is testing whether its wearable can be used to detect and classify normal sinus rhythm and atrial fibrillation. The latter is an irregular heart rhythm and the most common type of arrhythmia. It effects about one in 18 people, or 5% of the US population.

Having Afib is only a part of the problem. The other part is that a lot of people don’t know they have it. Early identification is key so that you can head off any potentially life-threatening developments before they arise.

Some 460 people, 22 years and older, participated in the study which Garmin concluded in July last year. Some of those have specifically been recruited because they have a known history of atrial fibrillation. Others have no known diagnosis of any arrhythmia. All participants were equipped with a single-lead Garmin ECG-enabled wearable device and the results were compared with a 12-lead ECG.

To date, the results of the study have not been published. Garmin may wait to upload those final results until they gain FDA approval. This is the route companies sometimes take.

Patent with USPTO for watch with ECG & blood pressure

Further clues that the company may be edging closer to publicly releasing the tech comes from a USPTO patent made public today (number 11350869). It describes a Garmin watch that can take ECG measurements.

The paperwork talks about a device with two contact electrical contact points. The first is located on a bezel or a push-button of the watch that the wearer would need to touch whilst taking a measurement. That is not necessary with the second point. The electrically-conductive plate is located on the back of the device so is constantly in contact with the wearer’s skin.

A processing element inside the device processes the first and second electrical bio signals, generates an ECG waveform, and an ECG image. A display graphically presents the ECG image as a sequence or stream of ECG images.

Interestingly, the patent also describes a blood pressure mode. Presumably this would be on-demand and measurements would require two contact points.

“The electrical HRM signal received by the system processing element 64 may include information or data regarding the pressure pulse in the blood resulting from a heartbeat.” the text reads.

“Unlike an ECG signal (an electrical signal) that travels nearly instantly from the user heart to the contact points of the electronic fitness device 20, the pressure pulse travels more slowly from the heart to the electronic fitness device 20. The system processing element 64 may calculate or determine an approximate distance from the user’s heart to electronic fitness device 20 or is entered by the wearer, then the system processing element 64 may calculate a pulse wave velocity as the distance divided by the time taken for the pulse wave to travel to the electronic fitness device 20 worn on the user’s wrist.”

When could we see a Garmin watch with ECG and/or blood pressure?

A patent is one thing but Garmin will still need regulatory approval for such a wearable. In the US this comes from the FDA. Only then will it be able to launch a consumer device that can be used for self-monitoring ECG and/or blood pressure.

Withings has shown just how difficult it can be to get the stamp of approval from the FDA. It took a couple of years to gain the go-ahead from the FDA for Scanwatch.

Essential reading: Best fitness trackers and health gadgets

Earlier this year DC Rainmaker found hidden ECG functionality in the Venu 2 Plus smartwatch. He did this by accessing an early version of the watch’s firmware. He notes that the functionality is far from being a finished product and that it only shows raw sensor data. On Venu 2 Plus taking am ECG works by placing your opposite thumb and index finger on the bezel. So the procedure is slightly different to what is described in the patent.

We saw recent launches of the Garmin Forerunner 955 and 255. Those are primarily running watches so not a good candidates for ECG and blood pressure measurements.

However, we are expecting a soonish launch of Venu Sq 2. That one and Venu are much better candidates for that type of functionality as they are Garmin’s all-purpose watches. Whether we see the tech included this year depends on the results of the Clinical Trial and length of time it takes to get FDA approval.

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