Comment by openasocket

They aren't clear what they mean by "97% accuracy". Does that mean 97% of people with arrhythmia are correctly diagnosed, or 97% of people are correctly diagnosed or not-diagnosed? If it's the latter, it's not very helpful at all. The number of people in the general population with arrhythmia is significantly less than 3%, so if this Apple Watch test says you have arrhythmia it is far more likely to be a false positive than a true positive.