Byron Black is scheduled to be given a lethal injection after a legal battle about whether a working defibrillator in his chest would cause him pain.

Tennessee is scheduled to execute death row inmate Byron Black on Tuesday morning despite concerns his heart implant will shock him repeatedly during the lethal injection. Black, 69, is one of the longest residents on the state's death row.

Tennessee's high court has ruled that a death row inmate can be executed without deactivating his implanted defibrillator.