In 2012, Mountain View-based AliveCor released KardiaMobile, a smartphone-connected device that could wirelessly record a single-lead ECG (aka EKG). KardiaMobile, however, is not just another novelty gadget for quantified selfers; it’s an FDA-approved Class 2 medical device that pairs with AliveCor’s comprehensive cardiac rhythm analysis service and integrates with select Omron blood pressure monitors. The device is now the most clinically-validated mobile ECG used by cardiac care physicians.
It naturally came as no surprise in late 2015 when AliveCor founder and Chief Medical Officer Dr. Dave Albert demonstrated a prototype of a mobile ECG for the recently-launched Apple Watch. Dr. Dave had shared with us earlier in the year his excitement for the Apple Watch as a potentially game-changing medical tool and hinted that he had figured out how to incorporate AliveCor’s innovative ECG technology into it. We’re pretty excited that the end result, called KardiaBand, was finally approved for sale in November and is making its way onto people’s wrists.
AliveCor was kind enough to send us the KardiaBand to try out for a few weeks. Read on for our thoughts on the first wearable ECG designed exclusively for the Apple Watch.
KardiaBand consists of two components: a specially-designed silicone watch band with a rounded square shaped cutout that houses a removable sensor module, and the metal and plastic sensor module itself.
The KardiaBand sensor module is an impressive feat of engineering. It’s effectively a KardiaMobile in a much, much smaller size. In an enclosure that is thinner than an iPhone, smaller than a dime, and lighter than $1.40 in dimes, AliveCor has managed to pack in a standard CR1620 battery that lasts two years, the electronics to sense the user’s ECG, and the ultrasonic audio hardware to send the recorded data to both the Apple Watch and/or iPhone in real-time.
Though the sensor module slightly increases the thickness of the watch band when inserted into it, it still feels comfortable to wear and doesn’t detract from the Apple Watch’s smooth curves and chic design. Speaking of design, we should note that the KardiaBand only comes in black silicone; you’re unfortunately out of luck if you had hoped to record your ECG during your next black tie affair. Also, while you might be able to take your Apple Watch (Series 2 or higher) swimming, the KardiaBand is only water resistant to 1 meter of shallow water, so you’ll want to remove the sensor module before hopping into the pool.
One interesting aside: KardiaBand and the larger KardiaMobile device operate in exactly the same way. They both use frequency modulated ultrasonic audio tones to send data to a microphone within a smartphone or smartwatch, and don’t require any kind of pairing. Moreover, since both the Apple Watch and our iPhone’s microphone could pick up the ultrasonic tones, we could see our ECG tracing simultaneously and in real-time on both the Apple Watch and iOS app.
When you want to make an ECG recording, simply open up either the Kardia app for Apple Watch or for iOS (or both) and tap the “Record EKG” button. You’ll be prompted to place your arms on a stable surface and hold your thumb on the sensor module. KardiaBand records the ECG across your heart using two electrodes: one electrode is already making contact with your wrist, and by touching the sensor module with your other thumb, you complete the electric circuit. While your ECG is recording, you can recite any symptoms you are feeling to be added as a voice recording. ECG recordings using the Apple Watch app are automatically sent to the iOS app and any voice recordings are automatically transcribed using voice recognition technology. From there, you can add tags that specify symptoms, physical activities, diet, and other information. The Kardia app also analyzes your ECG recording and determines whether it’s normal, unclassified, or unreadable, or a possible case of atrial fibrillation. During a couple stress-filled and extra caffeinated mornings, we had a couple ECG recordings marked as “Possible AF” and “Unclassified” due possibly to some extra PVC’s (premature ventricular contractions), but the recordings otherwise were free of noise, and the voice transcription was remarkably accurate.
Let’s talk a little more about the Kardia app for Apple Watch. From our experience, Apple Watch apps tend to be slower, stripped down versions of their iOS counterparts that serve more or less like a second display or a remote control. The Kardia app, however, took us by surprise. From within the app, you can start a recording and see your heart rate and ECG trace in real-time. The Apple Watch’s microphone is turned on to capture the ultrasonic signal from the KardiaBand and the voice recording of symptoms or additional notes if desired. And after the recording is complete, it is analyzed right on the watch to let you know if it’s normal, unclassified, or unreadable, or possible atrial fibrillation, and you can use the digital crown to scroll through it.
Another neat Apple Watch feature that is part of AliveCor’s premium membership ($9.99.month or $99/year) is “SmartRhythm” monitoring. What this does is put the watch into workout mode so its optical heart rate sensors and motion tracker are active. Using heart rate and activity data, SmartRhythm “evaluates it using a deep neural network to predict your heart rate pattern. If your heart rate differs from the neural network prediction, SmartRhythm will notify you to record an EKG.” This appears on the watch as a graph of your heart rate over the past hour, colored teal for an expected range and orange for a heart rate outside the predicted range. It’s kind of neat to visually track how your heart rate changes over the course of 60 minutes with this premium feature, and since it only uses the Apple Watch’s sensors, you can actually use it without a KardiaBand. Bear in mind, however, that the optical heart rate sensor uses a significant amount of battery, so you might be charging your watch more frequently if you leave this feature turned on for long periods of time.
Finally, a few brief notes about the Kardia iOS app. In addition to analyzing and storing your ECG recordings and history, you can generate printouts, PDFs, and reports for your own physician to review, or send it remotely to one of AliveCor’s contracted cardiac technicians or cardiologists to review for a fee. With AliveCor’s premium membership, the app will also allow you to record your weight, log your medication, monitor your resting heart rate, track your blood pressure with select Omron monitors, and utilize the SmartRhythm feature. All users can also connect all their data to Apple Health and learn more about how the heart works. AliveCor has an Android version of the Kardia app, but you’ll need an iOS device and an Apple Watch if you want to use it with a KardiaBand.
- Ready to use right out of the box with no setup or pairing
- Small, discreet, and comfortable to wear and use
- Well-designed and fully-featured Apple Watch and smartphone app
- Some features require a premium subscription
- Not compatible with Android
- SmartRhythm Monitoring features decreases the Apple Watch’s battery life and prevents using watch faces and the Activity app
Kudos to Dr. Dave and the AliveCor team for creating another great product that makes another Apple device more useful. We’ll just say it up front: KardiaBand is one of the most impressive examples of an Apple Watch accessory we’ve seen, health-related or not. The Kardia app is the best Apple Watch app we’ve used. We know from experience the resolution and amount of data required to record an ECG, and we’re blown away with how everything performs quickly and seamlessly. Thanks to the ingenious ultrasonic audio tone data transmission system, there’s hardly any pairing or setup required, and barely any lag between placing your thumb on the sensor and seeing your ECG tracing on the watch. Not everyone might need an AliveCor product, but if you own an Apple Watch and are concerned at all about the health of your ticker, consider placing a KardiaBand around your wrist.