After I had my heart-attack last year[1], I was asked to participate in a clinical trial of a device called a "Life Vest". I did so briefly, although I ditched it pretty quickly because it was too uncomfortable to sleep in. But this thing was basically a wearable EKG/defibrillator. It monitored your heart rhythm and, if you went into a bad rhythm, would actually give you a shock from the defibrillator. Handy if you were asleep or had already fallen unconscious and couldn't call for help.
Of course it gave you a warning buzz first and had a "cancel" button so you could avoid being shocked if you were actually still OK. And it wouldn't shock you, AFAIK, unless you were in a "shockable rhythm"[2].
Anyway, it's still a bit big, bulky and uncomfortable and I doubt you'll see millions of people wearing something like this anytime soon, but as things get lighter and cheaper and better, it might just become mainstream.
They are usually used as bridge devices until a patient can be scheduled for an AICD placement. Not all patients that need a permanent defibrillator are immediately fit for surgery and having a device like the Life Vest allows for them to be safely discharged from the hospital until it's time for surgery.
Yeah, I'm not entirely sure about all the rationales behind the device. I just agreed to do the clinical trial, then wore the thing about a day and ditched it. :-)
My doctors initially suggested that I might need a implantable defibrillator if my EF didn't recover sufficiently, but it turns out that by about 3 weeks after, my EF was back close to normal, so no defibrillator required. Now I'm hoping I can talk my cardiologist into taking me off of Metoprolol at some point, since I do some competitive endurance athletics and that stuff supposedly hurts your performance. And from what I've been reading, some newer research suggests that there's no real benefit to continuing to take it more than a year after an MI.
You generally want to wait six weeks after a heart attack before implanting an AICD, because the patient's heart frequently recovers to the point where an AICD won't be necessary at all. The LifeVest is supposed to bridge those six weeks.
It would have to be a pretty awkward device if you wanted to automatically detect a STEMI. An EKG capable of diagnosing a STEMI requires at least 9 electrodes (most use 10+), placed in very specific locations around the body.
