Will you definitely die if you stab yourself in your heart once?

Thinking both literally and of people with really bad health. If you stabbed the side that was not working properly  you would probably live and get your heart repaired when they see all the fat and plaque build up in and around it. So at least in one case it could very well save a life. Now in all reality this would most likely end anyones life who did this. Unless it was a freak accident and the blade sealed the wound until it could be removed safely and then repair the wound if possible. I have seen wierder wounds being survived.

It would seem to depend on the sort of stab wound you create, and what, if anything, you cut by doing it. Some people get medication delivered directly to the heart by injection (stabbed by a needle). That medical procedure is intended to save their life, rather than end it.

It seems likely you would feel the pain, until you passed out from
shock, as it takes a while to die from blood loss or asphyxiation.

Yes , heard that you will die instantly if you stab yourself in your heart , and it will be a painless death , cause doing this will cutoff blood supply to the brain that much I know,but I never tried it

Yes, stab me once and I am DEAD so I will live in the ground where dirt rots and where the devil lives... I am most definitely going to hell.

I'm going  to guess that get just one chance to find out

Probz unless you've got some emt's standing by...

If you managed to pierce your ribs and get to your heart then you'll have minimal chance of survival but if you were in a hospital then you could --> life support machine, but youd need a heart transplant pretty quickly =P....thinking of doing it coz you don't live in newcastle? =)

Yeah :/ if it was really deep then you would die