Bruno Sammartino’s death was reportedly the result of multiple organ failures due to heart issues.
Dave Meltzer mentioned in the latest issue of The Wrestling Observer Newsletter that Sammartino’s heart was damanged when he was 12 years old from a rheumatic fever. Sammartino was not aware of the issues with his heart until the last few years of his life.
Sammartino was in and out of the hospital for the last few months and was suffering from Diverticulitis. Sammartino apparently didn’t want people knowing about his condition and only a handful of people were aware of his health condition.
Given Sammartino’s condition, the belief is that his heavy training actually added about 15-20 years to his life but a good portion of his heart could no longer overcompensate for the damaged portion.