Miniature six-lead ECG is more accurate than Apple Watch [Updated Review]

AliveCor’s KardiaMobile 6L promises to be much more accurate than the heart monitor built into Apple Watch Series 4, and almost as easy to carry around. It’s the first personal ECG with three electrodes approved by the FDA to check the electrical activity of the heart.

We put this ultra-portable iPhone accessory to the test, as well as the more basic single-lead KardiaMobile, so don’t miss our reviews of each.

AliveCor KardiaMobile 6L review: 6-lead mobile ECG

This health sensor is designed to go everywhere with the user, and it’s correspondingly tiny. The KardiaMobile 6L is just 3.5 inches by 1.2 in. by 0.25 in. (9.0 cm x 3.0 cm x 0.72 cm) The weight is just 0.8 ounces (24 g).

It’s easily pocketable, as it’s not that much bigger than a bookmark. And AliveCor includes a case that allows this item to be attached to the iPhone.

There are two electrodes (1.2 in. by 1.2 in.) on the top of the KardiaMobile 6L, and then a third on the bottom. In use, the device is placed on the user’s bare left knee or ankle, and a finger from each hand is placed on the top electrodes. This arrangement, known as the Einthoven Triangle, allows cardiologists to view electrical activity in the heart from six perspectives or “leads.”

This is a medical device not a fashion accessory, but it nevertheless looks very professional.

It’s powered by a watch battery that AliveCor promises will only need to be replaced every couple of years.

AliveCor KardiaMobile 6L performance

Our test subject is a middle-aged man, making him old enough to potentially have heart problems but they’re unlikely. We used the KardiaMobile 6L as instructed by the Kardia application, which is free.

Taking a reading is straightforward. Tell the Kardia app to Record your EKG then place the sensor on the left knee or ankle while pressing the thumbs on the top electrodes. The app shows the data as it’s recording.

The KardiaMobile 6L also gives the option to take a single-lead reading. This doesn’t offer as much detail but doesn’t necessitate rolling up a pants’ leg.

The connection between AliveCor’s sensor and an iPhone or iPad requires Bluetooth. The app also requests access to the microphone so it can record the user’s comments while taking an ECG reading.

The application notifies the user if there are any medical problems found during the scan. All readings are then stored in a History section.

We’re not doctors and so lack the specialized knowledge to tell whether the information provided by KardiaMobile 6L is accurate. But Dr. Eric Topol, who is a cardiologist, said “I am impressed with the quality and simplicity of 6-lead smartphone ECG tracings which will unquestionably sharpen our ability to diagnose heart rhythm and conduction abnormalities.”

This medical device is approved by the FDA to detect Atrial Fibrillation (AFib), a form of irregular heart rhythm. It often goes undetected and brings increased risk of heart failure and stroke. The KardiaMobile 6L can also detect Bradycardia and Tachycardia, which literally mean “slow heart” and “fast heart”, respectively. While these are often benign, they can be indicative of heart disease or other health conditions, such as thyroid disease.

We took multiple readings each day over a week, and during this time almost all our reading came out Normal. We did receive a single false-positive for possible AFib, and once the scanner couldn’t diagnose a reading. Both came within a few minutes of each other. They were followed by a third reading that came out Normal.

AliveCor’s response: The developers of the KardiaMobile 6L said that this false positive was likely the result of the pre-release software we were using for testing. This accessory is set to debut soon, but our tests were done with a beta of the Kardia software.

Based on our experience, to ensure accurate readings we suggest the user relax, sit up straight, breathe normally and don’t burp. Anyone who gets a reading that shows a problem should wait a few minutes and take a second reading before calling a doctor.

The Kardia software can be used to help track the user’s weight if they want to enter that data. It can also store blood pressure readings, either entered manually or with an AliveCor OMROM monitor.

AliveCor KardiaMobile 6L final thoughts

This product is the happy combination of functionality and portability. It’s small enough to carry everywhere and does its job with no fuss.

An Apple Watch can take a single-lead ECG reading, but the KardiaMobile 6L gathers much more data about the electrical functioning of the heart. Again, we’re not doctors but it’s hard to imagine a medical situation where more information is bad.

AliveCor just unveiled its six-lead scanner and it’s currently available for pre-order. The cost is $149. For comparison, an Apple Watch with ECG starts at $399. Of course, the wearable does a lot more than just take ECG readings.

Buy From: AliveCor

AliveCor KardiaMobile mini-review

There’s a single-lead version of this ECG monitor that costs less, but it also gathers less data. This original KardiaMobile has a pair of electrodes on the top, without the third on the bottom, so using it just requires a finger from each hand. The hardware is slightly smaller and thinner.

This version uses the same Kardia application, which offers the same features.The only difference is it has less data to display.

The single lead KardiaMobile is $99.

Buy From: AliveCor

AliveCor provided Cult of Mac with a review unit for this article. See our reviews policy, and check out more stuff we recommend.