American actor Nicholas Brendon, best known for playing Xander Harris in the series 'Buffy the Vampire Slayer,' died unexpectedly in the early morning hours. According to a family statement, Brendon died in his sleep at age 54. The official cause of death has not yet been released, but about three years ago it was revealed that he suffered a heart attack and subsequently experienced medical complications from a heart defect, as well as cauda equina syndrome, which causes damage to the spinal cord.

