It has been called shell shock, battle fatigue, soldier’s heart and, most recently, post traumatic stress disorder, or PTSD. Now, military officers and psychiatrists are embroiled in a heated debate over whether to change the name of a condition as old as combat. The potential new moniker: post traumatic stress injury. Military officers and some psychiatrists say dropping the word “disorder’’ in favor of “injury’’ will reduce the stigma that stops troops from seeking treatment.