I have three questions? My 51 year old brother died very suddenly and unexpectedly just 10 days ago. No autopsy was done, but they did say they found a blood clot in his heart. Apparently, he had no warning or symptoms whatsoever because he was found face down on the ground (He had been out for a morning walk.)with his arms at his sides. He had had no previous heart or health problems prior to this. Could this be the cause of death? How might the clot have formed in the first place? And, would the tendency to form an unexpected blood clot be hereditary?