Methods and systems are provided that utilize reference morphology templates as morphology based filters to reduce false or inappropriate ST episode detections when an ST shift episode is otherwise diagnosed. The methods and systems provide ST morphology discrimination. The methods and systems sense cardiac signals of a heart, obtain a reference morphology template based on at least one baseline cardiac signal associated with a normal physiology waveform, and identify a potential ST segment shift from the cardiac signals. The methods and systems compare the cardiac signals to the reference morphology template to derive a morphology indicator representing a degree to which the cardiac signals match the reference morphology template and declare the potential ST segment shift to be an actual ST segment shift based on the morphology indicator.
