"Only could be useful if you could get the data out of the unit in a usable form, and if that form was reasonably close to a known standard EKG output."
Totally agree - that's why I'll just keep an eye out and still never depend on it. The idea of an over-cautious alarm that goes off if my heart stops in the middle of the night for no reason does kind of appeal. Read up on BrS - it's a bit of a worry - there have been villages in SE Asia where multiple people have died overnight for no reason seemingly. It's these stories that inspired Wes Craven to write A Nightmare on Elm St.
Biting the hand that feeds IT
