(Cincinnati) -- After medical studies linked the use of Tasers to heart failure, Cincinnati Police Chief James Craig has announced changes in the way officers can use the stun guns.

Officers have been re-trained to deploy the Taser at a suspect's back, instead of their chest.  They've also been told the head, and abdomen are not acceptable either.  However, Chief Craig says if an officer is attacked, and the back isn't a viable target, a chest shot is okay.

Craig says officers must also take into consideration a suspect's surroundings, and whether they could be injured in a fall, after being shocked with the Taser.

He says officers must also consider the "severity of a crime... whether the suspect poses an immediate threat to the safety of officers or others; Whether the suspect is actively resisting arrest, or attempting to evade arrest by flight."