I think the criteria for donation are most easily met by people who die as a result of something like a vehicle collision, but an otherwise healthy person who experiences sudden heart failure may have viable organs... From the reporting, this donor was not otherwise healthy, but maybe the symptoms were not known at the time or dismissed for some reason.
Not really. Organs from people who have died are almost always nonviable. So when it comes to vehicle collision victims, only people who are slowly dieing of internal hemorrhaging are used. Sudden heart failure organs are bad for two reasons: first, if the heart actually fails, you have minutes before organs are nonviable. Second, the medication that's used for trying to keep the heart beating will actually accelerate death, including organ death, if it doesn't work.
Most organs come from from people, usually braindead, who are definitely going to die, but you have days or at least hours before the body actually loses the fight. And even then the extraction process needs to be started quickly, because in the process of dieing the body will, as it's losing blood, ie. power and oxygen, one-by-one cut off blood flow from organs to try to keep the heart, lungs and brain alive. Most organs that have had their blood flow cut off by the body can't be transplanted, so extraction needs to happen before that point.
