Racehorse Charismatic died from complications of a broken pelvis:
A necropsy exam cannot determine whether the fracture in Charismatic's pelvis was new, or an old injury lurking which may have been exacerbated from some kind of incident in his stall. The initial necropsy report suggests the pelvis incurred a trauma in the stall which damaged the internal ileac artery, a part of the blood supply running directly from the horse's aorta.
“Talking to colleagues of mine, everybody's had a case or two in their life where they just found a horse in the stall dead, and this is what they found,” said Bell. “I think we have a little bit more information on the human side of things. These are usually people who were injured in car crashes, and it has a very high mortality in people. I don't know that too much is known about it [in horses] except this is something that happens and there's nothing you can do about it.”
Once the blood supply in this part of the body is damaged, Bell and Waldridge agreed there is nothing that can be done for a horse to repair it, even with immediate action.
Bell and Waldridge are still awaiting a copy of the full necropsy report, but do not believe cardiac arrest played a role in the horse's injury by precipitating a fall.