- Medical record of acute ischemia as evidenced on ECG or positive cardiac biomarkers in the interim between CCTA and CTP. Electrocardiographic evidence of acute ischemia includes acute STEMI (ST elevation equal to or greater than 1mm in two or more leads), ST segment depression and/or T wave inversion (not known to be old and thought to be evidence of ongoing ischemia). Positive cardiac biomarkers include elevated troponin, myoglobin, and/or creatinine phosphokinase MB fraction).