This feature is key to diagnosing atrial fibrillation, because as the name suggests, patients often don't feel symptoms during an episode.Atrial fibrillation is the most common sustained heart rhythm disorder, and it increases the risk for heart disease and stroke. An estimated 2.2 million adults in the United States have been diagnosed with it, and that number is expected to increase to more than 5 million by 2040.Devices that treat patients who don't even feel sickâEUR"that is a real example of innovation and serving an unmet need in the market.