The health-tracking potential of the Apple Watch might just be one of the device's stronger selling points. These capabilities are now set to expand with the US Food and Drug Administration (FDA) today clearing the first medical device for the Apple Watch, in the form of a sensor that tucks into the band to detect irregular heartbeats.

AliveCor's KardiaBand is based on the same electrocardiogram (EKG) technology seen its earlier offering: a smartphone case that received FDA approval way back in 2012. EKG devices work by tracking the electric activity of the heart through electrode patches, gathering data on heart rhythm, blood flow and abnormalities.

For a number of years now, tech companies and research teams have been working on ways to squeeze them into all kinds of products and make them more accessible. These include bathroom scales, driver's seats, fitness bands and other smartwatches. And now it's the Apple Watch's turn.

With the KardiaBan fitted to the Apple Watch and the companion app open on the device, wearers hit record and place their thumb on the sensor just below the watch face. This takes a 30-second recording and instantly displays the results, indicating if the heartbeat is normal or if there are signs of atrial fibrillation, the most common kind of heart arrhythmia.

A new feature called SmartRhythm, also announced by AliveCor today, uses artificial intelligence combined with the Apple Watch's built in heart rate and activity sensors to track the relationship between physical activity and the heart's behavior. If it detects that the two are out of sync, it will suggest the user take an EKG with the KardiaBand.

Available from today, the KardiaBand is priced at US$199 but also requires a subscription to AliveCor's Premium service, which costs $99 a year. The video below demonstrates how it works.

Source: AliveCor

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