Even if it could check a trop, that's a pretty late indicator. If you're having the big one, you're going to be dead before your troponin spikes.

Is that right? When I worked in medical instrumentation, I was always told that TnI was a leading marker.

It will take up to 8 hours for troponin levels to rise after the onset of symptoms (typically 3-4).

ER nurse here - some STEMIs I've taken care of had negative initial trop's (not all though). The 4 hr delta should of course be positive though - I don't typically check the 4 hr repeat for STEMIs though because they're long gone out of the ED to the cath lab then to CVICU.

I could imagine the thing detecting Vfib but it would need to use some good AI signal processing to exclude artifacts. Elevated ST segments, probably not, even with good AI.

OTOH doesn't the EKG feature only work when you touch the watch with your other hand? In which case it would be useless for heart attacks that caused you to lose consciousness.