1. A computer readable program storage unit encoded with instructions that, when executed by a computer, perform a method for indicating an occurrence of a state change, comprising: obtaining data relating to at least a portion of a heart beat complex from a patient; comparing said at least said portion of said heart beat complex with a corresponding portion of a first reference heart beat complex template of said patient; and, indicating an occurrence of a state change based upon a determination that said heart beat complex fails to match said first reference heart beat complex template.