l am an aspiring writer and am currently working on novel. l am looking for the guidelines that a donor heart must meet. l mean like does it matter how the donor dies? What characteristics do the donor and then person receiving the heart have to share? Any and all information will be extremely useful and greatly appreciated, I've been doing research for several hours now but l am having a hard time finding exactly what I am looking for, so thanks in advance for all your help.

a donor heart comes from people who either died accidentally or from an illness that doesnt render the heart unhealthy. the decision to donate is done by the donor. they usually have an organ donation card. if they dont, the closest relative of the possible donor will decide. the receipient & the donor should pass several cross matchings (i.e. blood type, size of the heart, cell compatibility). for the receipient, it is usually the first person in the list of candidates & is compatible with the donor who gets the heart (unless the donor specified who will recieve his organ before he dies).

''Finding a donor can be difficult. In heart transplantation, the healthy heart must come from a person who recently died or is on life-support and is brain dead. This is different than a kidney transplant, because a kidney may be donated by a living person. Timing is very important because there is no good way to keep a donor heart alive for long periods of time.''
http://nlm.nih.gov/medlineplus/ency/article/003003.htm