The story of David Bennett, age 57, who had severe cardiac failure and was denied a traditional human heart transplant from several programs when he ultimately agreed to the experimental xenotransplant. On day 34, the patient showed no signs of rejection of the porcine heart, but by day 49, sudden diastolic thickening and antibody-mediated failure of the xenograft prevented any lifesaving measures, and he died on day 60.