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.

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.

Significantly less invasive. Not everybody needs a defib after a heart attack, especially in the case of minor, atrial infarctions.

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.