Tennessee executed death row inmate Byron Black on Tuesday despite raised concerns about his implanted heart device, which could cause a "prolonged and torturous execution."

Byron Black, 69, was executed for the 1988 South Nashville murders of his ex-girlfriend Angela Clay and her two daughters Latoya, 9, and Lakeisha, 6.

Lawyers for Byron Black, found guilty of three murders, had argued that an execution may be more painful because of his heart implant.