- AMI definition is accordance with the third universal definition of ESC /ACCF/ AHA/ WHF Task Force10, detection of a rise and/or fall of cardiac biomarker values [preferably cardiac troponin (cTn) I or T] with at least one value above the 99th percentile upper reference limit (URL) and with at least one of the following: Symptoms of ischemia. New or presumed new significant ST-segment-T wave (ST-T) changes or new left bundlebranch block (LBBB).