In addition, the company launched a new version of the band today in the US with a feature called SmartRhythm. That uses Apple's built-in heart rate sensor and AI algorithms to warn you if your heart rate is elevated when you're not exercising or doing strenuous activities.

FDA clearance means that AliveCor can sell and market it as a medical device, but users don't need doctor approval to use it. "The average consumer doesn't know what a normal sinus rhythm looks like or what atrial fibrillation looks like. Yet the FDA has cleared our individual algorithms," AliveCor CEO and former Google exec Vic Gundotra told Business Insider. "We have the clinical studies to prove it."

These capabilities will allow people to easily and discreetly check their heart rhythms when they may be abnormal, capturing essential information to help doctors identify the issue and inform a clear path of care to help manage AFib, a leading cause of stroke, and other serious conditions.

The device uses AI to determine what range of heart and EKG readings are correct for individual users, rather than just a generic group. If the band detects problems, it will advise you to take a more accurate EKG test. You can also use AliveCor's voice recognition tech to describe your symptoms aloud, and the watch will combine all the data. It can even email an analysis to your doctor.

AliveCor's KardiaBand is now available for a reasonable $200, but you'll need a premium $99 per year ($10 per month) subscription to get all the features and analysis. That means it's more or less aimed at patients who might have reasons to worry about abnormal heart rhythms because of a family history or previous diagnosis.

That will put older patients squarely in the target market, but Gundotra said that ease-of-use was high on the design list for AliveCor. "The members of our team are people who build consumer products and so we know what it takes to run a product that a 55 year old can use," he said.