Diagnosis of Myocardial Infarction The diagnosis of myocardial infarction is based on clinical story and troponin leak.Troponin levels can be normal or low due to very early symptoms or high due to a large infarction or due to spontaneous reperfusion with washout of viable ischemic tissue.If there is ST segment elevation,there is a strong suggestion that a coronary artery is occluded or nearly occluded,but that needs confi rmation by angiography and ventriculography.