An inmate executed by Tennessee without deactivating his implanted defibrillator said he was hurting badly shortly after the lethal injection began, according to several witnesses. Byron Black was put to death despite uncertainty about whether the device would shock his heart when the lethal chemicals took effect.

The Tennessee Supreme Court ruled on July 31 that Byron Black could be executed without deactivating his implanted defibrillator, with the high court noting that requiring that the device be deactivated "amounted to a stay of execution, which is not within the lower court’s power," according to the Associated Press.

Byron Black's execution marked the first time a man has been put to death with a working defibrillator in his chest, experts say.