I had never considered an Apple Watch. I believed it to be too costly for what it offered. The selling point today was their heart study with Stanford and that the watch will detect irregular heartbeats. I'm genetically predisposed to atrial fibrillation [1] (TL;DR Abnormal heart rhythm), and having a watch that can alert me that my heart rhythm is deviating from a normal rhythm is cheap insurance against a poor cardiac outcome.
For me, its medical telemetry first, and a phone second.
Hmm or just go to a doctor and ask for a long term EKG maybe. That's what I did. I had to wear some measuring equipment for a day and then I had the result (broken heart). I don't think this changes from day to day so you might want to get a check every few year.
No, atrial fibrillation occurs in distinct episodes (imagine your heart occasionally having an epileptic seizure that lasts a few hours) and it can be difficult to get an EKG when you suspect something is wrong.
For me, its medical telemetry first, and a phone second.
[1] https://en.wikipedia.org/wiki/Atrial_fibrillation