A heart plug was a medically implanted device seen in David Lynch's 1984 film version of Dune. Presumably used on human Slaves or enemies the Harkonnens wished to torture to death, it was a small object sewed into the chest of the victim, seemingly over the heart. When a small tab in the center of the plug was pulled out, the victim's blood would flow out through the opening and the victim would bleed to death.
The heart plug was never explained in the film and does not appear in the Frank Herbert novels. It is implied to be a controlling device that carried the threat of instant death if removed. However, the Baron Harkonnen himself also had a heart plug. Given this fact, it has been speculated that the heart plug may be part an internal body filtering system essential for living on the heavily polluted world of Giedi Prime.
