The Apple Watch already has a heart rate sensor, and it can even help. But it’s not an FDA-approved medical device that can be officially used to detect heart conditions like atrial fibrillation… at least, not yet. But now you can add a strap to the watch that does just that.
AliveCor’s Kardia Band is the first FDA-approved heart rate band for the Apple Watch. Unlike the Apple Watch’s optical heart rate technology, the Kardia Band uses your finger or thumb to complete an electrical circuit via two metal contacts: one for your finger, one that rests against your wrist. It works with Apple Watch Series 1, 2 and 3 models — that is, every version except the original “Series Zero” model.
The spot EKG reading takes 30 seconds and is designed to measure when stationary, not active. AliveCor’s Kardia app tracks heart rate continuously with the Apple Watch’s sensors and then pings you to take an extra EKG reading when your heart rate seems out of place with where your activity and previous history would indicate, using what AliveCor says is AI that learns over time.
EKG readings can be stored in-app, imported into Apple Health, or sent to your doctor. The $200 band also requires a $99-a-year subscription service to use the app’s sharing features, cloud storage, and incorporation of weight and blood pressure measurements. For an additional fee, AliveCor exports results for analysis by either a “Cardiac Technician” ($9, 1 hour turnaround) or a “US Board Certified Cardiologist” ($19, 24 hours).
The band seemed to drain the Apple Watch battery faster than usual (it uses always-on heart rate by default). And AliveCor makes a less expensive $99 standalone device, the Kardia Mobile (which I haven’t tested) that does something similar. But the advantage of the Apple Watch-connected Kardia Band is that it can make EKG readings completely on its own, away from an iPhone and even offline. For those who need an on-the-spot more accurate heart rate measurement for medical purposes, this could be an interesting option. My handful of initial attempts said my EKGs were “normal.”
Medically approved heart rate accessories for fitness trackers and smartwatches aren’t common yet, but they may be on the rise in the year to come. And, eventually, fitness trackers might be medically approved for accurate heart rate on their own. For now, the Kardia Band is a bridge to where heart rate on health wearables could go next.